remind/remind.1

.\" $Id: remind.1,v 1.10 1997-08-31 17:03:26 dfs Exp $
.TH REMIND 1 "31 July 1997"
.UC 4
.SH NAME
remind \- a sophisticated reminder service
.SH SYNOPSIS
.B remind [\fIoptions\fR] \fIfilename\fR [\fIdate\fR] [\fI*rep\fR] [\fItime\fR]
.SH DESCRIPTION
\fBRemind\fR reads the supplied \fIfilename\fR and executes the commands
found in it.  The commands are used to issue reminders and alarms.  Each
reminder or alarm can consist of a message sent to standard output, or
a program to be executed.
.PP
If \fIfilename\fR is specified as a single dash '-', then \fBRemind\fR
takes its input from standard input.  This also implicitly enables
the \fB\-o\fR option, described below.
.SH OPTIONS
\fBRemind\fR has a slew of options.  If you're new to the program,
ignore them for now and skip to the section "Reminder Files".
.TP
.B \-n
The \fB\-n\fR option causes \fBRemind\fR to print the \fBnext\fR occurrence
of each reminder in a simple calendar format.  You can sort this by
date by piping the output through \fBsort(1)\fR.
.TP
.B \-r
The \fB\-r\fR option disables \fBRUN\fR directives and the \fBshell()\fR
function
.TP
.B \-c\fR\fIn\fR
The \fB\-c\fR option causes \fBRemind\fR to produce a calendar which is sent to
standard output.  If you supply a number \fIn\fR, then a calendar will
be generated for \fIn\fR months, starting with the current month.  By
default, a calendar for only the current month is produced.  If \fIn\fR
starts with '+', then a calendar for \fIn\fR weeks is produced.
.TP
.B \-w\fR\fIcol\fR[,\fIpad\fR[,\fIspc\fR]]]
The \fB\-w\fR option specifies the output width, padding and spacing
of the formatted calendar output.  \fICol\fR specifies the number of
columns in the output device, and defaults to 80.  \fIPad\fR specifies
how many lines to use to "pad" empty calendar boxes.  This defaults to
5.  If you have many reminders on certain days, which make your calendar
too large to fit on a page, you can try reducing \fIpad\fR to make the
empty boxes smaller.  \fISpc\fR specifies how many blank lines to leave
between the day number and the first reminder entry.  It defaults to 1.
.RS
.PP
Any of \fIcol\fR, \fIpad\fR or \fIspc\fR can be omitted, providing you
provide the correct number of commas.  Don't use any spaces in the option.
.RE
.TP
.B \-s\fR\fIn\fR
The \fB\-s\fR option is very similar to the \fB\-c\fR option, except
that the output calendar is not formatted.  It is listed in a "simple
format" which can be used as input for more sophisticated calendar-drawing
programs.  If \fIn\fR starts with "+", then it is interpreted as a number
of weeks.
.TP
.B \-p\fR\fIn\fR
The \fB\-p\fR option is very similar to the \fB\-s\fR option, except
that the output contains additional information for use by the
\fBrem2ps\fR program, which creates a PostScript calendar.  For this
option, \fIn\fR cannot start with "+"; it must specify a number of months.
.TP
.B \-m
The \fB\-m\fR option causes the \fB\-c\fR or \fB\-p\fR options to produce
a calendar whose first column is Monday rather than Sunday.
(This conforms to the international standard.)
.TP
.B \-v
The \fB\-v\fR option makes the output of \fBRemind\fR slightly more verbose.
.TP
.B \-o
The \fB\-o\fR option causes \fBRemind\fR to ignore all \fBONCE\fR directives.
.TP
.B \-t
The \fB\-t\fR option causes \fBRemind\fR to trigger all non-expired reminders,
regardless of the \fIdelta\fR supplied for each reminder.
.TP
.B \-h
The \fB\-h\fR option ("hush...") suppresses certain warning and information
messages.  In particular, if no reminders are triggered, this mode
produces no output.
.TP
\fB\-a\fR (UNIX and OS/2 only)
The \fB\-a\fR option causes \fBRemind\fR not to immediately trigger timed
reminders which would also be queued.  It also causes \fBRemind\fR not to
place timed reminders in a calendar.
.TP
\fB\-q\fR (UNIX and OS/2 only)
The \fB\-q\fR option causes \fBRemind\fR not to queue timed reminders
for later execution.
.TP
\fB\-f\fR (UNIX and OS/2 only)
The \fB\-f\fR option causes \fBRemind\fR to remain in the foreground
when processing queued reminders, rather than forking off
a background process to handle them.
.TP
.B \-e
The \fB\-e\fR option diverts error messages (normally sent to the
standard error stream) to the standard output stream.
.TP
.B \-d\fR\fIchars\fR
The \fB-d\fR option enables certain debugging modes.  The \fIchars\fR
specify which modes to enable:
.RS 2
.TP
.B e
Echo all input lines
.TP
.B x
Trace all expression evaluation
.TP
.B t
Display all trigger date computation
.TP
.B v
Dump the variable table after execution of the reminder script
.TP
.B l
Echo lines when displaying error messages
.RE
.TP
\fB\-g\fR[\fBa|d\fR[\fBa|d\fR[\fBa|d\fR]]]
Normally, reminders are issued in the order in which they are encountered
in the reminder script.  The \fB\-g\fR option cause \fBRemind\fR to
sort reminders by date and time prior to issuing them.  The optional
\fBa\fR and \fBd\fR characters specify the sort order (ascending or
descending) for the date, time and priority fields.  See the section "Sorting
Reminders" for more information.
.TP
\fB\-b\fR[\fIn\fR]
Set the time format for the calendar and simple-calendar outputs.  \fIN\fR
can range from 0 to 2, with the default 0.  A value of 0 causes times
to be inserted in 12-hour (am/pm) format.  1 causes times to be inserted
in 24-hour format, and 2 inhibits the automatic insertion of times in the
calendar output.
.TP
\fB\-x\fR[\fIn\fR]
Sets the iteration limit for the \fBSATISFY\fR clause of a \fBREM\fR
command.  Defaults to 150.
.TP
\fB\-k\fR\fIcmd\fR
Instead of simply printing \fBMSG\fR-type
reminders, this causes them to be passed to the specific \fIcmd\fR.
You must use '%s' where you want the body to appear, and may need to
enclose this option in quotes.  Note that all shell characters in the
body of the reminder are escaped with a backslash, and the entire body
of the reminder is passed as a single argument.  Note that this option
\fBoverrides\fR the \fB\-r\fR option and the \fBRUN OFF\fR command.
.PP
.RS
As an example, suppose you have an X Window program called xmessage, which
pops up a window and displays its invocation arguments.  You could use:
.PP
.nf
		remind '-kxmessage %s &' ...
.fi
.PP
to have all of your \fBMSG\fR-type reminders processed using xmessage.
.PP
A word of warning:  It is very easy to spawn dozens of xmessage processes
with the above technique.  So be very careful.  Also, the \fIcmd\fR is passed
as an argument to \fBsprintf()\fR.  If you use formatting directives other
than %s, or use more than one %s directive, there's a good chance that
you'll crash \fBRemind\fR.  Finally, because all shell and whitespace
characters are escaped, the program you execute with the \fB\-k\fR
option must be prepared to handle the entire message as a single argument.
.RE
.TP
\fB\-z\fR[\fIn\fR] (UNIX and OS/2 only)
Runs \fBRemind\fR in the daemon mode.  If \fIn\fR is supplied, it
specifies how often (in minutes) \fBRemind\fR should wake up to
check if the reminder script has been changed.  \fIN\fR defaults
to 5, and can range from 5 to 60.  Note that the use of the
\fB\-z\fR option also enables the \fB\-f\fR option.
.TP
\fB\-u\fR\fIname\fR  (UNIX version only)
Runs \fBRemind\fR with the uid and gid of the user specified by \fIname\fR.
The option changes the uid and gid as described, and sets the
environment variables HOME, SHELL and USER to the home directory, shell,
and user name, respectively, of the specified user.  LOGNAME is also
set to the specified user name.  This option is meant for
use in shell scripts which mail reminders to all users.  Note that
as of Remind 3.0.17, using \fB\-u\fR implies \fB\-r\fR -- the RUN
directive and shell() functions are disabled.
.PP
.RS
Non-root users can also use the \fB\-u\fR option.  However, in this
case, it only changes the environment variables as described above.
It does not change the effective uid or gid.
.RE
.TP
\fB\-i\fR\fIvar\fR\fB=\fR\fIexpr\fR
Sets the value of the specified \fIvar\fR to \fIexpr\fR, and \fBpreserves\fR
\fIvar\fR.  \fIExpr\fR can be any valid \fBRemind\fR expression.  See the
section "Initializing Variables on the Command Line" for more details.
.PP
If you supply a \fIdate\fR on the command line, it must consist of
\fIday month year\fR, where \fIday\fR is the day of the month,
\fImonth\fR is at least the first three letters of the English name
of the month, and \fIyear\fR is a year (all 4 digits) from 1990 to
about 2075.  You can leave out the \fIday\fR, which then defaults to 1.
.PP
If you do supply a \fIdate\fR on the command line, then \fBRemind\fR uses
it, rather than the actual system date, as its notion of "today."
This lets you create calendars for future months, or test to see
how your reminders will be triggered in the future.  Similarly,
you can supply a \fItime\fR (in 24-hour format -- for example, 17:15) to
set \fBRemind\fR's notion of "now" to a particular time.  Supplying
a \fItime\fR on the command line also implicitly enables the \fB\-q\fR
option and disables the \fB\-z\fR option.
.PP
In addition, you can supply a \fIrepeat\fR parameter, which has the
form *\fInum\fR.  This causes \fBRemind\fR to be run \fInum\fR times,
with the date incrementing on each iteration.  You may have to enclose
the parameter in quotes to avoid shell expansion.  See the subsection
"Repeated Execution" in the section "Calendar Mode" for more
information.
.SH REMINDER FILES
.PP
\fBRemind\fR uses scripts to control its operation.  You can use any
text editor capable of creating plain ASCII files to create a
\fBRemind\fR script.  The commands inside a script can range from the
very simple and almost immediately understandable:
.PP
.nf
	REM 6 Jan MSG David's birthday
.fi
.PP
to the baroque and obscure:
.PP
.nf
	REM [trigger(date(thisyear, 1, 1) + 180)] ++5 OMIT \\
	sat sun BEFORE MSG [ord(thisyear-1980)] payment due %b!
.fi
.PP
A reminder file consists of commands, with one command per line.  Several
lines can be continued using the backslash character, as in the above
example.  In this case, all of the concatenated lines are treated as a
single line by \fBRemind\fR.  Note that if an error occurs, \fBRemind\fR
reports the line number of the last line of a continued line.
.PP
\fBRemind\fR ignores blank lines, and lines beginning with the '#' or ';'
characters.  You can use the semicolon as a comment character if you
wish to pass a \fBRemind\fR script through the C pre-processor, which
interprets the '#' character as the start of a pre-processing
directive.
.PP
\fBRemind\fR is not case sensitive; you can generally use any mixture of upper-
or lower-case for commands, parameters, invocation options, etc.
.SH THE REM COMMAND
.PP
The most powerful command in a \fBRemind\fR script is the \fBREM\fR command.
This command is responsible for issuing reminders.
Its syntax is:
.PP
.RS
\fBREM\fR [\fBONCE\fR] [\fIdate_spec\fR]
[\fIback\fR]
[\fIdelta\fR]
[\fIrepeat\fR]
[\fBPRIORITY\fR \fIprio\fR]
[\fBSKIP\fR | \fBBEFORE\fR | \fBAFTER\fR]
[\fBOMIT\fR \fIomit_list\fR]
[\fBAT\fR \fItime\fR [\fItdelta\fR] [\fItrepeat\fR]]
[\fBSCHED\fR \fIsched_function\fR]
[\fBWARN\fR \fIwarn_function\fR]
[\fBUNTIL\fR \fIexpiry_date\fR]
[\fBSCANFROM\fR \fIscan_date\fR]
\fBMSG\fR | \fBMSF\fR | \fBRUN\fR | \fBCAL\fR | \fBSATISFY\fR |
\fBPS\fR | \fBPSFILE\fR
.I body
.RE
.PP
The parts of the \fBREM\fR command can be specified in any order, except
that the \fIbody\fR must come immediately after the \fBMSG\fR,
\fBRUN\fR, \fBCAL\fR, \fBPS\fR, \fBPSFILE\fR or \fBSATISFY\fR keyword.
.PP
The \fBREM\fR token is optional, providing that the remainder
of the command cannot be mistaken for another \fBRemind\fR command
such as \fBOMIT\fR or \fBRUN\fR.  The portion of the \fBREM\fR command
before the \fBMSG\fR, \fBMSF\fR \fBRUN\fR, \fBCAL\fR or \fBSATISFY\fR clause
is called a \fItrigger\fR.
.PP
.B "MSG, MSF, RUN, CAL, PS and PSFILE"
.PP
These keywords denote the \fItype\fR
of the reminder.  (\fBSATISFY\fR is more complicated and will be explained
later.)  A \fBMSG\fR-type reminder normally prints a message to the standard
output, after passing the \fIbody\fR through a special substitution filter,
described in the section "The Substitution Filter."  However, if you have
used the \fB\-k\fR command-line option, then \fBMSG\fR-type reminders are
passed to the appropriate program.  Note that the options \fB\-c\fR,
\fB\-s\fR, \fB\-p\fR and \fB\-n\fR disable the \fB\-k\fR option.
.PP
The \fBMSF\fR keyword is almost the same as the \fBMSG\fR keyword,
except that the reminder is formatted to fit into a paragraph-like
format.  Three system variables control the formatting of \fBMSF\fR-type
reminders - they are \fB$FirstIndent\fR, \fB$SubsIndent\fR and
\fB$FormWidth\fR.  They are discussed in the section "System Variables."
The \fBMSF\fR keyword causes the spacing of your reminder to be altered -
extra spaces are discarded, and two spaces are placed after periods and
other characters, as specified by the system variables \fB$EndSent\fR and
\fB$EndSentIg\fR.  Note that if the body of the reminder includes
newline characters (placed there with the %_ sequence), then the newlines
are treated as the beginnings of new paragraphs, and the \fB$FirstIndent\fR
indentation is used for the next line.  You can use two consecutive
newlines to have spaced paragraphs emitted from a single reminder body.
.PP
A \fBRUN\fR-type
reminder also passes the \fIbody\fR through the substitution filter, but
then executes the result as a system command.  A \fBCAL\fR-type reminder
is used only to place entries in the calendar produced when \fBRemind\fR
is run with the \fB\-c\fR, \fB\-s\fR or \fB\-p\fR options.
.PP
A \fBPS\fR or \fBPSFILE\fR-type reminder is used to pass PostScript code
directly to the printer when producing PostScript calendars.  This can
be used to shade certain calendar entries (see the psshade() function),
include graphics in the calendar,
or almost any other purpose you can think of.  You
should not use these types of reminders unless you are an expert PostScript
programmer.  The \fBPS\fR and \fBPSFILE\fR reminders are ignored unless
\fBRemind\fR is run with the \fB\-p\fR option.  See the section
"More about PostScript" for more details.
.PP
.B DATE SPECIFICATIONS
.PP
A \fIdate_spec\fR consists of zero to four parts.
These parts are
.I day
(day of month),
.I month
(month name),
.I year
and
.I weekday.
.I Month
and
.I weekday
are the English names of months and weekdays.  At least the first three
characters must be used.  The following are examples of the various parts of a
.I date_spec:
.TP
.I day:
1, 22, 31, 14, 3
.TP
.I month:
JANUARY, feb, March, ApR, may, Aug
.TP
.I year:
1990, 1993, 2030, 95 (interpreted as 1995).  The year can range
from 1990 to 2075.
.TP
.I weekday:
Monday, tue, Wed, THU, Friday, saturday, sundAy
.PP
Note that there can be several
.I weekday
components separated by spaces in a
.I date_spec.
.PP
.B INTERPRETATION OF DATE SPECIFICATIONS
.PP
The following examples show how date specifications are interpreted.
.PP
1. Null date specification - the reminder is triggered every day.
The trigger date for a specific run is simply the current system date.
.PP
2. Only
.I day
present.  The reminder is triggered on the specified day of each month.
The trigger date for a particular run is the closest such day to the
current system date.  For example:
.nf
	REM 1 MSG First of every month.
	REM 31 MSG 31st of every month that has 31 days.
.fi
.PP
3. Only
.I month
present.  The reminder is triggered every day of the specified month.
Example:
.nf
	REM Feb MSG Every day in February
.fi
.PP
4.
.I day
and
.I month
present.  Examples:
.nf
	REM 6 Jan MSG Every 6th of January
	REM Feb 29 MSG Every 29th of February
.fi
.PP
5.  Only
.I year
present. Example:
.nf
	REM 1991 MSG Every day in 1991
.fi
.PP
6.
.I year
and
.I day
present.  Examples:
.nf
	REM 1 1990 MSG 1st of every month in 1990
	REM 1992 23 MSG 23rd of every month in 1992
.fi
.PP
7.
.I year
and
.I month
present.  Examples:
.nf
	REM Feb 1991 MSG Every day in Feb 1991
	REM 1992 September MSG Every day in Sept 1992
.fi
.PP
8.
.I year, month
and
.I day
present.  Examples:
.nf
	REM 8 Jan 1991 MSG 8th January 1991.
	REM 1992 March 9 MSG 9th March 1992.
.fi
.PP
9.
.I weekday
only.  Examples:
.nf
	REM Sat MSG Every Saturday
	REM Mon Tue Wed Thu Fri MSG Every working day
	REM Monday Wednesday MSG Every Monday and Wednesday
.fi
.PP
10.
.I weekday
and
.I day
present.  Examples:
.nf
	REM Sat 1 MSG First Saturday of every month
	REM Mon Tue Wed Thu Fri 15 \\
		MSG 1st working day after 15th of every month
.fi
.PP
11.
.I weekday
and
.I month
present.  Examples:
.nf
	REM Mon March MSG Every Monday in March
	REM Mon Tue Wed Thu Fri Feb MSG Every working day in February
.fi
.PP
12.
.I weekday, month
and
.I day
present.  Examples:
.nf
	REM Mon 1 March MSG First Monday in March
	REM Sat Sun 15 July MSG First Sat or Sun on or after 15 July
.fi
.PP
13.
.I weekday
and
.I year
present.  Example:
.nf
	REM Sat Sun 1991 MSG Every Saturday and Sunday in 1991
.fi
.PP
14.
.I weekday, day
and
.I year
present.  Examples:
.nf
	REM Mon 15 1990 MSG 1st Mon after 15th of every month in 1990
	REM Mon Tue Wed Thu Fri 1 1990 \\
		MSG 1st working day of every month in 1990
.fi
.PP
15.
.I weekday, month
and
.I year
present.  Example:
.nf
	REM Mon Wed 1991 Feb MSG Every Mon and Wed in Feb 1991.
.fi
.PP
16.
.I weekday, day, month
and
.I year
present.  Example:
.nf
	REM Mon Tue Wed Thu Fri 28 Oct 1990 \\
		MSG 1st working day on or after 28 October 1990.
.fi
.PP
Note that when both
.I weekday
and
.I day
are specified,
.B Remind
chooses the first date on or after the specified
.I day
which also satisfies the
.I weekday
constraint.  It does this by picking the first date on or after the specified
.I day
which is listed in the list of
.I weekdays.
Thus, a reminder like:
.PP
.nf
	REM Mon Tue 28 Oct 1990 MSG Hi
.fi
.PP
would be issued only on Monday, 29 October, 1990.  It would not be issued
on Tuesday, 30 October, 1990, since the 29th is the first date to satisfy
the
.I weekday
constraints.
.PP
.B BACKWARD SCANNING
.PP
Sometimes, it is necessary to specify a date as being a set amount of
time before another date.  For example, the last Monday in a given
month is computed as the first Monday in the next month, minus 7 days.
The \fIback\fR specification in the reminder is used in this case:
.PP
.nf
	REM Mon 1 -7 MSG Last Monday of every month.
.fi
.PP
A \fIback\fR is specified with one or two dashes followed by an integer.
This causes \fBRemind\fR to move "backwards" from what would normally be the
trigger date.  The difference between \-\-7 and \-7 will be explained
when the \fBOMIT\fR keyword is described.
.PP
.B ADVANCE WARNING
.PP
For some reminders, it is appropriate to receive advance warning of the
event.  For example, you may wish to be reminded of someone's birthday
several days in advance.  The \fIdelta\fR portion of the \fBREM\fR command
achieves this.  It is specified as one or two "+" signs followed by a number
\fIn\fR.  Again, the difference between the "+" and "++" forms will
be explained under the \fBOMIT\fR keyword.
\fBRemind\fR will trigger the reminder on computed trigger date, as well as
on each of the \fIn\fR days before the event.  Here are some examples:
.PP
.nf
	REM 6 Jan +5 MSG Remind me of birthday 5 days in advance.
.fi
.PP
The above example would be triggered every 6th of January, as well as the
1st through 5th of January.
.PP
.B PERIODIC REMINDERS
.PP
We have already seen some built-in mechanisms for certain types of
periodic reminders.  For example, an event occurring every Wednesday
could be specified as:
.PP
.nf
	REM Wed MSG Event!
.fi
.PP
However, events which do not repeat daily, weekly, monthly or yearly require
another approach.  The \fIrepeat\fR component of the \fBREM\fR command
fills this need.  To use it, you must completely specify a date (year, month
and day, and optionally weekday.)  The \fIrepeat\fR component is an asterisk
followed by a number specifying the repetition period in days.
.PP
For example, suppose you get paid every second Wednesday, and your
last payday was Wednesday, 28 October, 1992.  You can use:
.PP
.nf
	REM 28 Oct 1992 *14 MSG Payday
.fi
.PP
This issues the reminder every 14 days, starting from the calculated trigger
date.  You can use \fIdelta\fR and \fIback\fR with \fIrepeat.\fR  Note,
however, that the \fIback\fR is used only to compute the initial
trigger date; thereafter, the reminder repeats with the specified
period.  Similarly, if you specify a weekday, it is used only to calculate
the initial date, and does not affect the repetition period.
.PP
.B SCANFROM
.PP
The \fBSCANFROM\fR keyword is for advanced \fBRemind\fR programmers
only, and will be explained in the section "Details about Trigger Computation"
near the end of this manual.  Note that \fBSCANFROM\fR is available only
in versions of \fBRemind\fR from 03.00.04 up.
.PP
.B PRIORITY
.PP
The \fBPRIORITY\fR keyword must be followed by a number from 0 to 9999.
It is used in calendar mode and when sorting reminders.  If two reminders
have the same trigger date and time, then they are sorted by priority.
If the \fBPRIORITY\fR keyword is not supplied, a default priority of 5000
is used.  (This default can be changed by adjusting the system variable
\fB$DefaultPrio\fR.  See the section "System Variables" for more
information.)
.PP
.B EXPIRY DATES
.PP
Some reminders should be issued periodically for a certain time, but then
expire.  For example, suppose you have a class every Friday, and that your
last class is on 11 December 1992.  You can use:
.PP
.nf
	REM Fri UNTIL 11 Dec 1992 MSG Class today.
.fi
.PP
Another example:  Suppose you have jury duty from 30 November 1992 until
4 December 1992.  The following reminder will issue the message every day
of your jury duty, as well as 2 days ahead of time:
.PP
.nf
	REM 30 Nov 1992 *1 +2 UNTIL 4 Dec 1992 MSG Jury duty
.fi
.PP
Note that the \fIrepeat\fR of *1 is necessary; without it, the reminder
would be issued only on 30 November (and the two days preceding.)
.PP
.B THE ONCE KEYWORD
.PP
Sometimes, it is necessary to ensure that reminders are run only once
on a given day.  For example, if you have a reminder which makes a backup
of your files every Friday:
.PP
.nf
	REM Fri RUN do_backup
.fi
.PP
(Here, \fIdo_backup\fR is assumed to be a program or shell script which
does the work.)  If you run \fBRemind\fR from your .login script, for
example, and log in several times per day, the \fIdo_backup\fR program
will be run each time you log in.  If, however, you use the \fBONCE\fR
keyword in the reminder, the \fBRemind\fR checks the last access date of
the reminder script.  If it is the same as the current date, \fBRemind\fR
assumes that it has already been run, and will not issue reminders containing
the \fBONCE\fR keyword.
.PP
Note that if you view or edit your reminder script, the last access date
will be updated, and the \fBONCE\fR keyword will not operate properly.
If you start \fBRemind\fR with the \fB\-o\fR option, then the \fBONCE\fR
keyword will be ignored.
.PP
.B LOCALLY OMITTING WEEKDAYS
.PP
The \fBOMIT\fR portion of the \fBREM\fR command is used to "omit" certain
days when counting the \fIdelta\fR or \fIback\fR.  It is specified using
the keyword \fBOMIT\fR followed by a list of weekdays.  Its action is
best illustrated with examples:
.PP
.nf
	REM 1 +1 OMIT Sat Sun MSG Important Event
.fi
.PP
This reminder is normally triggered on the first of every month, as well
as the day preceding it.  However, if the first of the month falls on a
Sunday or Monday, then the reminder is triggered starting from the
previous Friday.  This is because the \fIdelta\fR of +1 does not count
Saturday or Sunday when it counts backwards from the trigger date to
determine how much advance warning to give.
.PP
Contrast this with the use of "++1" in the above command.  In this case,
the reminder is triggered on the first of each month, as well as the day
preceding it.  The omitted days are counted.
.PP
.nf
	REM 1 -1 OMIT Sat Sun MSG Last working day of month
.fi
.PP
Again, in the above example, the \fIback\fR of \-1 normally causes the
trigger date to be the last day of the month.  However, because of the
\fBOMIT\fR clause, if the first of the month falls on a Sunday or Monday,
the trigger date is moved backwards past the weekend to Friday.  (If you
have globally omitted holidays, the reminder will be moved back past them,
also.  See "The OMIT command" for more details.)
.PP
By comparison, if we had used "\-\-1", the reminder would be triggered on
the last day of the month, regardless of the \fBOMIT\fR.
.PP
.B TIMED REMINDERS
.PP
Timed reminders are those which have an \fBAT\fR keyword followed
by a \fItime\fR and optional \fItdelta\fR and \fItrepeat\fR.  The \fItime\fR
must be specified in 24-hour format, with 0:00 representing midnight,
12:00 representing noon, and 23:59 representing one minute to midnight.
You can use either a colon or a period to separate the hours from the
minutes.  That is, 13:39 and 13.39 are equivalent.
.PP
\fBRemind\fR treats timed reminders specially.  If the trigger date
for a timed reminder is the same as the current system date, the
reminder is queued for later activation.  When \fBRemind\fR has
finished processing the reminder file, it puts itself in the
background, and activates timed reminders when the system time reached
the specified time.  (Unfortunately, the MS-DOS version does not have
this ability -- most of this section applies only to the UNIX and OS/2
versions.)
.PP
If the trigger date is \fInot\fR the same as the system date, the reminder
is not queued.
.PP
For example, the following reminder, triggered every working day, 
will emit a message telling you to
leave at 5:00pm:
.PP
.nf
	REM Mon Tue Wed Thu Fri AT 17:00 MSG Time to leave!
.fi
.PP
The following reminder will be triggered on Thursdays and Fridays,
but will only be queued on Fridays:
.PP
.nf
	REM Fri ++1 AT 13:00 MSG Lunch at 1pm Friday.
.fi
.PP
The \fItdelta\fR and \fItrepeat\fR have the same form as a \fIrepeat\fR
and \fIdelta\fR, but are specified in minutes.  For example, this reminder
will be triggered at 12:00pm as well as 45 minutes before:
.PP
.nf
	REM AT 12:00 +45 MSG Example
.fi
.PP
The following will be issued starting at 10:45, every half hour until 11:45,
and again at noon.
.PP
.nf
	REM AT 12:00 +75 *30 MSG Example2
.fi
.PP
The "+75" means that the reminder is issued starting 75 minutes before noon;
in other words, at 10:45.  The *30 specifies that the reminder is subsequently
to be issued every 30 minutes.  Note that the reminder is always issued at
the specified time, even if the \fItdelta\fR is not a multiple of the
\fItrepeat\fR.  So the above example is issued at 10:45am, 11:15am, 11:45am,
and 12:00pm.  Note that in the time specification, there is no distinction
between the "+" and "++" forms of \fItdelta\fR.
.PP
Normally, \fBRemind\fR will issue timed reminders as it processes the reminder
script, as well as queuing them for later.  If you do not want \fBRemind\fR to
issue the reminders when processing the script, but only to queue them
for later, use the \fB\-a\fR command-line option.  If you do not want
reminders to be queued for later, use the \fB\-q\fR command-line
option.
.PP
Normally, \fBRemind\fR forks a background process to handle queued reminders.
If you want \fBRemind\fR to remain in the foreground, use the \fB\-f\fR
command-line option.  This is useful, for example, in .xinitrc
scripts, where you can use the command:
.PP
.nf
	remind -fa myreminders &
.fi
.PP
This ensures that when you exit X-Windows, the \fBRemind\fR process is killed.
.PP
.B WARNING ABOUT TIMED REMINDERS
.PP
Note:  If you use user-defined functions or variables (described later)
in the bodies of timed reminders, then when the timed reminders are
activated, the variables and functions have the definitions which were
in effect at the end of the reminder script.  These definitions may
\fInot\fR necessarily be those which were in effect at the time the reminder
was queued.
.PP
.B THE SCHED AND WARN KEYWORDS
.PP
The \fBSCHED\fR keyword allows more precise control over the triggering
of timed reminders, and the \fBWARN\fR keyword allows precise control
over the advance triggering of all types of reminders.
However, discussion must be deferred until after
expressions and user-defined functions are explained.  See the subsection
"Precise Scheduling" further on.
.PP
.SH THE SUBSTITUTION FILTER
.PP
Before being processed, the body of a
.B REM
command is passed through a substitution filter.  The filter scans for
sequences "%x" (where "x" is any letter and certain other characters)
and performs substitutions as
shown below.  (All dates refer to the trigger date of the reminder.)
.TP
.B %a
is replaced with "on \fIweekday, day month, year\fR"
.RS
For example, consider the reminder:
.PP
REM 18 Oct 1990 +4 MSG Meeting with Bob %a.
.PP
On 16 October 1990, it would print "Meeting with Bob on Thursday, 18 October,
1990."
.PP
On 17 October 1990, it would print "Meeting with Bob tomorrow."
.PP
On 18 October 1990, it would print "Meeting with Bob today."
.RE
.TP
.B %b
is replaced with "in \fIdiff\fR day's time" where
.I diff
is the
.B actual
number of days between the current date and the trigger date.
(\fBOMITs\fR have no effect.)
.RS
For example, consider:
.PP
REM 18 Oct 1990 +4 MSG Meeting with Bob %b.
.PP
On 16 October 1990, it would print "Meeting with Bob in 2 days' time."
.PP
On 17 October 1990, it would print "Meeting with Bob tomorrow."
.PP
On 18 October 1990, it would print "Meeting with Bob today."
.RE
.TP
.B %c
is replaced with "on \fIweekday\fR"
.RS
Example: REM 18 Oct 1990 +4 MSG Meeting with Bob %c.
.PP
On 16 October 1990, it would print "Meeting with Bob on Thursday."
.PP
On 17 October 1990, it would print "Meeting with Bob tomorrow."
.PP
On 18 October 1990, it would print "Meeting with Bob today."
.RE
.TP
.B %d
is replaced with "\fIday\fR", the day of the month.
.TP
.B %e
is replaced with "on \fIdd/mm/yyyy\fR"
.TP
.B %f
is replaced with "on \fImm/dd/yyyy\fR"
.TP
.B %g
is replaced with "on \fIweekday, day month\fR"
.TP
.B %h
is replaced with "on \fIdd/mm\fR"
.TP
.B %i
is replaced with "on \fImm/dd\fR"
.TP
.B %j
is replaced with "on \fIweekday, month day-th, year\fR"  This form appends the
characters "st", "nd", "rd" or "th" to the day of the month, as appropriate.
.TP
.B %k
is replaced with "on \fIweekday, month day-th\fR"
.TP
.B %l
is replaced with "on \fIyyyy/mm/dd\fR"
.TP
.B %m
is replaced with "\fImonth\fR", the name of the month.
.TP
.B %n
is replaced with the number (1 to 12) of the month.
.TP
.B %o
is replaced with " (today)" if and only if the current system date is the same
as the date being used by
.B Remind
as the current date.  Recall that you can specify a date for
.B Remind
to use on the command line.  This substitution is not generally useful in a
.B REM
command, but is useful in a
.B BANNER
command.  (See "The BANNER Command.")
.TP
.B %p
is replaced with "s" if the
.I diff
between the current date and the trigger date is not 1.  You can use this
to construct reminders like:
.RS
REM 1 Jan +4 MSG %x day%p to go before New Year!
.RE
.TP
.B %q
is replaced with "'s" if the
.I diff
between the trigger date and the current date is 1.  Otherwise, it is replaced
with "s'"  This can be used as follows:
.RS
REM 1 Jan +4 MSG New Year in %x day%q time!
.RE
.TP
.B %r
is replaced with the day of the month (01 to 31) padded with a leading zero
if needed to pad to two digits.
.TP
.B %s
is replaced with "st", "nd", "rd" or "th" depending on the day of the month.
.TP
.B %t
is replaced with the number of the month (01 to 12) padded to two digits
with a leading zero.
.TP
.B %u
is replaced with "on \fIweekday, day-th month, year\fR"  This is similar
to
.B %a
except that "st", "nd", "rd" or "th" is added to the
.I day
as appropriate.
.TP
.B %v
is replaced with "on \fIweekday, day-th month\fR"
.TP
.B %w
is replaced with "\fIweekday\fR", the name of the day of the week.
.TP
.B %x
is replaced with the
.I diff
between the current date and the trigger date.  The
.I diff
is defined as the actual number of days between these two dates;
.B OMITs
are not counted.  (Strict date subtraction is performed.)
.TP
.B %y
is replaced with "\fIyear\fR", the year of the trigger date.
.TP
.B %z
is replaced with "\fIyy\fR", the last two digits of the year.
.TP
.B %_
(percent-underscore) is replaced with a newline.  You can use this to
achieve multi-line reminders.
.TP
.B %1
is replaced with "now", "\fIm\fR minutes from now", "\fIm\fR minutes ago",
"\fIh\fR hours from now", "\fIh\fR hours ago", "\fIh\fR hours and \fIm\fR
minutes from now" or "\fIh\fR hours and \fIm\fR minutes ago", as appropriate
for a timed reminder.  Note that unless you specify the \fB\-a\fR option,
timed reminders will be triggered like normal reminders, and thus a timed
reminder which occurred earlier in the day may be triggered.  This
causes the need for the "...ago" forms.
.TP
.B %2
is replaced with "at \fIhh\fR:\fImm\fRam" or "..pm" depending on the
.B AT
time of the reminder.
.TP
.B %3
is replaced with "at \fIhh\fR:\fImm\fR" in 24-hour format.
.TP
.B %4
is replaced with "\fImm\fR" where \fImm\fR is the number of minutes between
"now" and the time specified by \fBAT\fR.  If the \fBAT\fR time is
earlier than the current time, then the result is negative.
.TP
.B %5
is replaced with "\fIma\fR" where \fIma\fR is the absolute value of the number
produced by \fB%4\fR.
.TP
.B %6
is replaced with "ago" or "from now", depending on the relationship between
the \fBAT\fR time and the current time.
.TP
.B %7
is replaced with the number of hours between the \fBAT\fR time and the
current time.  It is always non-negative.
.TP
.B %8
is replaced with the number of minutes between the \fBAT\fR time and
the current time, after the hours (\fB%7\fR) have been subtracted out.
This is a number ranging from 0 to 59.
.TP
.B %9
is replaced with "s" if the value produced by \fB%8\fR is not 1.
.TP
.B %0
is replaced with "s" if the value produced by \fB%7\fR is not 1.
.TP
.B %!
is replaced with "is" if the current time is before the \fBAT\fR time,
or "was" if it is after.
.TP
.B %@
is similar to \fB%2\fR but displays the current time.
.TP
.B %#
is similar to \fB%3\fR but displays the current time.
.TP
.B 
%"
(percent-doublequote) is removed.  This sequence is not 
used by the substitution filter,
but is used to tell \fBRemind\fR which text to include in a calendar
entry when the \fB\-c\fR, \fB\-s\fR or \fB\-p\fR option is chosen.
See "Calendar Mode"
.PP
Notes:
.TP
o
.B Remind
normally prints a blank line after each reminder; if the last character
of the body is "%", the blank line will not be printed.
.TP
o
Substitutions a, b, c, e, f, g, h, i, j, k, l, u and v all are replaced
with "today" if the current date equals the trigger date, or "tomorrow"
if the trigger date is one day after the current date.  Thus, they are
.B not
the same as substitutions built up from the simpler %w, %y, etc.
sequences.
.TP
o
Any of the substitutions dealing with time (0 through 9 and '!')
produce undefined results if used in a reminder which does not have
an \fBAT\fR keyword.  Also, if a reminder has a \fIdelta\fR and may
be triggered on several days, the time substitutions ignore the date.  Thus,
the \fB%1\fR substitution may report that a meeting is in 15 minutes, for
example, even though it may only be in 2 days time, because a \fIdelta\fR has
triggered the reminder.  It is recommended that you use the time substitutions
only in timed reminders with no \fIdelta\fR which are designed to be
queued for timed activation.
.TP 
o
Capital letters can be used in the substitution sequence, in which case
the first character of the substituted string is capitalized (if it is
normally a lower-case letter.)
.TP 
o
All other characters following a "%" sign are simply copied.  In particular,
to get a "%" sign out, use "%%" in the body.  To start the body of a reminder
with a space, use "% ", since
.B Remind
normally scans for the first non-space character after a
.B MSG,
.B CAL
or
.B RUN
token.
.SH THE OMIT COMMAND
.PP
In addition to being a keyword in the \fBREM\fR command,
\fBOMIT\fR is a command in its own right.  Its syntax is:
.PP
.RS
\fBOMIT\fR \fIday\fR \fImonth\fR [\fIyear\fR]
.RE
.PP
The \fBOMIT\fR command is used to "globally" omit certain days, which
are usually holidays.  These globally-omitted days are skipped by the
"\-" and "+" forms of \fIback\fR and \fIdelta\fR.  Some examples:
.PP
.nf
	OMIT 1 Jan
	OMIT 7 Sep 1992
.fi
.PP
The first example specifies a holiday which occurs on the same date each
year - New Year's Day.  The second example specifies a holiday which
changes each year - Labour Day.  For these types of holidays, you
must create an \fBOMIT\fR command for each year.  (Later, in the
description of expressions and some of the more advanced features of
\fBRemind\fR, you will see how to automate this for some cases.)
.PP
For convenience, you can use a \fIdelta\fR and \fBMSG\fR or \fBRUN\fR
keyword in the \fBOMIT\fR command.  The following sequences are exactly
equivalent:
.PP
.nf
	OMIT 1 Jan
	REM 1 Jan +4 MSG New year's day is %b!

	and

	OMIT 1 Jan +4 MSG New year's day is %b!
.fi
.PP
.B THE BEFORE, AFTER AND SKIP KEYWORDS
.PP
Normally, days which are omitted, whether by a global \fBOMIT\fR command
or the local \fBOMIT\fR keyword in a \fBREM\fR statement, only affect the
counting of the \-\fIback\fR or the +\fIdelta\fR.  For example, suppose
you have a meeting every Wednesday.  Suppose, too, that you have indicated
11 Nov as a holiday:
.PP
.nf
	OMIT 11 Nov +4 MSG Remembrance Day
	REM Wed +1 MSG Code meeting %b.
.fi
.PP
The above sequence will issue a reminder about a meeting for 11 November 1992,
which is a Wednesday.  This is probably incorrect.  There are three
options:
.TP
.B BEFORE
This keyword moves the reminder to before any omitted days.  Thus, in
the above example, use of \fBBEFORE\fR would cause the meeting reminder
to be triggered on Tuesday, 10 November 1992.
.TP
.B AFTER
This keyword moves the reminder to after any omitted days.  In the above
example, the meeting reminder would be triggered on Thursday, 12 November
1992.
.TP
.B SKIP
This keyword causes the reminder to be skipped completely on any omitted
days.  Thus, in the above example, the reminder would not be triggered
on 11 November 1992.  However, it would be triggered as usual on the following
Wednesday, 18 November 1992.
.PP
The \fBBEFORE\fR and \fBAFTER\fR keywords move the trigger date of a
reminder to before or after a block of omitted days, respectively.
Suppose you normally run a backup on the first day of the month.  However,
if the first day of the month is a weekend or holiday, you run the backup
on the first working day following the weekend or holiday.  You could use:
.PP
.nf
	REM 1 OMIT Sat Sun AFTER RUN do_backup
.fi
.PP
Let's examine how the trigger date is computed.  The \fB1\fR specifies
the first day of the month.  The local \fBOMIT\fR keyword causes the
\fBAFTER\fR keyword to move the reminder forward past weekends.
Finally, the \fBAFTER\fR keyword will keep moving the reminder forward
until it has passed any holidays specified with global \fBOMIT\fR
commands.
.SH THE INCLUDE COMMAND
.PP
\fBRemind\fR allows you to include other files in your reminder script,
similar to the C preprocessor #include directive.  For example, your
system administrator may maintain a file of holidays or system-wide
reminders.  You can include these in your reminder script as follows:
.PP
.nf
	INCLUDE /usr/share/remind/holidays
	INCLUDE /usr/share/remind/reminders
.fi
.PP
(The actual pathnames vary from system to system - ask your system
administrator.)
.PP
\fBINCLUDE\fR files can be nested up to a depth of 8.
.PP
If you specify a filename of "-" in the \fBINCLUDE\fR command, \fBRemind\fR
will begin reading from standard input.
.SH THE RUN COMMAND
.PP
If you include other files in your reminder script, you may not always
entirely trust the contents of the other files.  For example, they
may contain \fBRUN\fR-type reminders which could be used to access your
files or perform undesired actions.  The \fBRUN\fR command can restrict
this:  If you include the command \fBRUN OFF\fR in your top-level reminder
script, any reminder or expression which would normally execute a system
command is disabled.  \fBRUN ON\fR will re-enable the execution of
system commands.  Note that the \fBRUN ON\fR command can \fIonly\fR be used
in your top-level reminder script; it will \fInot\fR work in any files
accessed by the \fBINCLUDE\fR command.  This is to protect you from someone
placing a \fBRUN ON\fR command in an included file.  However, the
\fBRUN OFF\fR command can be used at top level or in an included file.
.PP
If you run \fBRemind\fR with the \fB\-r\fR command-line option,
\fBRUN\fR-type reminders and the \fBshell()\fR function will be disabled,
regardless of any \fBRUN\fR commands in the reminder script.  However,
any command supplied with the \fB\-k\fR option will still be executed.
.PP
One use of the \fBRUN\fR command is to provide a secure interface
between \fBRemind\fR and the \fBElm\fR mail system.  The \fBElm\fR
system can automatically scan incoming mail for reminder or calendar
entries, and place them in your calendar file.  To use this feature,
you should set the calendar filename option under \fBElm\fR to be something
like "~/.reminders.in", \fInot\fR your main reminder file!  This is
so that any \fBRUN ON\fR commands mailed to you can never be activated.
.PP
Then, you can use the \fBElm\fR \fIscan message for calendar entries\fR
command to place reminders prefaced by "->" into .reminders.in.  In
your main .reminders file, include the following lines:
.PP
.nf
	RUN OFF   # Disable RUN
	INCLUDE .reminders.in
	RUN ON    # Re-enable RUN
.fi
.PP
In addition, \fBRemind\fR on UNIX contains a few other security
features.  It will not read a file which is group- or world-writable.
It will not run set-uid.  If it reads a file you don't own, it will
disable RUN and the shell() function.  And if it is run as \fIroot\fR,
it will only read files owned by \fIroot\fR.
.PP
.SH THE BANNER COMMAND
.PP
When \fBRemind\fR first issues a reminder, it prints a message like this:
.PP
.nf
	Reminders for Friday, 30th October, 1992 (today):
.fi
.PP
(The banner is not printed if any of the calendar-producing options
is used, or if the \fB\-k\fR option is used.)
.PP
The \fBBANNER\fR command lets you change the format.  It should appear
before any \fBREM\fR commands.  The format is:
.PP
.RS
\fBBANNER\fR \fIformat\fR
.RE
.PP
The \fIformat\fR is similar to the \fIbody\fR of a \fBREM\fR command.  It
is passed through the substitution filter, with an implicit trigger of
the current system date.  Thus, the default banner is equivalent to:
.PP
.nf
	BANNER Reminders for %w, %d%s %m, %y%o:
.fi
.PP
You can disable the banner completely with BANNER %.  Or you can create
a custom banner:
.PP
.nf
	BANNER Hi - here are your reminders for %y/%t/%r:
.fi
.SH CONTROLLING THE OMIT CONTEXT
.PP
Sometimes, it is necessary to temporarily change the global \fBOMITs\fR
which are in force for a few reminders.  Three commands allow you to do
this:
.TP
.B PUSH-OMIT-CONTEXT
This command saves the current global \fBOMITs\fR on an internal stack.
.TP
.B CLEAR-OMIT-CONTEXT
This command clears all of the global \fBOMITs\fR, starting you off with
a "clean slate."
.TP
.B POP-OMIT-CONTEXT
This command restores the global \fBOMITs\fR which were saved by the most
recent \fBPUSH-OMIT-CONTEXT\fR.
.PP
For example, suppose you have a block of reminders which require a clear
\fBOMIT\fR context, and that they also introduce unwanted global \fBOMITs\fR
which could interfere with later reminders.  You could use the following
fragment:
.PP
.nf
	PUSH-OMIT-CONTEXT	# Save the current context
	CLEAR-OMIT-CONTEXT	# Clean the slate
	# Block of reminders goes here
	POP-OMIT-CONTEXT	# Restore the saved omit context
.fi
.SH EXPRESSIONS
.PP
In certain contexts, to be described later, \fBRemind\fR will accept
expressions for evaluation.  \fBRemind\fR expressions resemble C
expressions, but operate on different types of objects.
.PP
.B DATA TYPES
.PP
\fBRemind\fR expressions understand four types of objects:
.TP
.B INT
The \fBINT\fR data type consists of the integers representable in one machine
word.  The \fBINT\fR data type corresponds to the C "int" type.
.TP
.B STRING
The \fBSTRING\fR data type consists of strings of characters.  It is
somewhat comparable to a C character array, but more closely resembles
the string type in BASIC.
.TP
.B TIME
The \fBTIME\fR data type consists of times of the day.  The \fBTIME\fR
data type is internally stored as an integer representing the number
of minutes since midnight.
.TP
.B DATE
The \fBDATE\fR data type consists of dates (later than 1 January 1990.)
Internally, \fBDATE\fR objects are stored as the number of days since
1 January 1990.
.PP
.B CONSTANTS
.PP
The following examples illustrate constants in \fBRemind\fR expressions:
.TP
.B INT constants
12, 36, -10, 0, 1209
.TP
.B STRING constants
"Hello there", "This is a test", "\\n\\gosd\\w", ""
.PP
.RS
Note that the empty string is represented by "", and that
backslashes in a string are \fInot\fR interpreted specially, as in they are
in C.
.RE
.TP
.B TIME constants
12:33, 0:01, 14:15, 16:42, 12.16, 13.00, 1.11
.PP
.RS
Note that \fBTIME\fR constants are written in 24-hour format.  Either the
period or colon can be used to separate the minutes from the hours.
However, Remind will consistently output times using only one separator
character.  (The output separator character is chosen at compile-time.)
.RE
.TP
.B DATE constants
\fBDATE\fR constants are expressed as 'yyyy/mm/dd' or 'yyyy-mm-dd',
and the single
quotes \fImust\fR be supplied.  This distinguishes date constants
from division or subtraction of integers.  Examples:
.PP
.RS
\'1993/02/22', '1992-12-25', '1999/01/01'
.PP
Note that \fBDATE\fR constants are \fIprinted\fR
without the quotes.  Although either '-' or '/' is accepted as a date
separator on input, when dates are printed, only one will be used.  The
choice of whether to use '-' or '/' is made at compile-time.
Note also that versions
of \fBRemind\fR prior to 03.00.01 did not support date constants.  In those
versions, you must create dates using the \fBdate()\fR function.  Also,
versions prior to 03.00.02 did not support the '-' date separator.
.RE
.PP
.B OPERATORS
.PP
\fBRemind\fR has the following operators.  Operators on the same line
have equal precedence, while operators on lower lines have lower precedence
than those on higher lines.  The operators approximately correspond to
C operators.
.PP
.nf
	!  -     (unary logical negation and arithmetic negation)
	*  /  %		
	+  -
	<  <=  >  >=
	==  !=
	&&
	||
.fi
.PP
.B DESCRIPTION OF OPERATORS
.PP
.TP
.B !
Logical negation.  Can be applied to an \fBINT\fR type.  If the operand
is non-zero, returns zero.  Otherwise, returns 1.
.TP
.B \-
Unary minus.  Can be applied to an \fBINT\fR.  Returns the negative
of the operand.
.TP
.B *
Multiplication.  Returns the product of two \fBINT\fRs.
.TP
.B /
Integer division.  Returns the quotient of two \fBINT\fRs, discarding the
remainder.
.TP
.B %
Modulus.  Returns the remainder upon dividing one \fBINT\fR by another.
.TP
.B +
Has several uses.  These are:
.PP
.RS
\fBINT\fR + \fBINT\fR - returns the sum of two \fBINT\fRs.
.PP
\fBINT\fR + \fBTIME\fR or \fBTIME\fR + \fBINT\fR - returns a \fBTIME\fR
obtained by adding
\fBINT\fR minutes to the original \fBTIME\fR.
.PP
\fBINT\fR + \fBDATE\fR or \fBDATE\fR + \fBINT\fR - returns a \fBDATE\fR
obtained by adding \fBINT\fR days to the original \fBDATE\fR.
.PP
\fBSTRING\fR + \fBSTRING\fR - returns a \fBSTRING\fR which is the
concatenation of the two original
\fBSTRING\fRs.
.PP
\fBSTRING\fR + anything or anything + \fBSTRING\fR -
converts the non-\fBSTRING\fR
argument to a \fBSTRING\fR, and then performs concatenation.  See
the \fBcoerce()\fR function.
.RE
.TP
.B \-
Has several uses.  These are:
.PP
.RS
\fBINT\fR - \fBINT\fR - returns the difference of two \fBINT\fRs.
.PP
\fBDATE\fR - \fBDATE\fR - returns (as an \fBINT\fR) the difference in days
between two \fBDATE\fRs.
.PP
\fBTIME\fR - \fBTIME\fR - returns (as an \fBINT\fR) the difference in minutes
between two \fBTIME\fRs.
.PP
\fBDATE\fR - \fBINT\fR - returns a \fBDATE\fR which is \fBINT\fR days
earlier than
the original \fBDATE\fR.
.PP
\fBTIME\fR - \fBINT\fR - returns a \fBTIME\fR which is \fBINT\fR minutes
earlier
than the original \fBTIME\fR.
.RE
.TP
.B <, <=, >, and >=
These are the comparison operators.  They can take operands of any type,
but both operands must be of the same type.  The comparison operators
return 1 if the comparison is true, or 0 if it is false.  Note that
string comparison is done following the lexical ordering of
characters on your system, and that upper and lower case \fIare\fR
distinct for these operators.
.TP
.B ==, !=
== tests for equality, returning 1 if its operands are equal, and
0 if they are not.  != tests for inequality.
.PP
.RS
If the operands are not of the same type, == returns 0 and != returns
1.  Again, string comparisons are case-sensitive.
.RE
.TP
.B &&
This is the logical AND operator.  Both of its operands must be of
type \fBINT\fR.  It returns 1 if both operands are non-zero, and 0
otherwise.
.TP
.B ||
This is the logical OR operator.  Both of its operands must be of
type \fBINT\fR.  It returns 1 if either operand is non-zero, and 0
otherwise.
.PP
.B NOTES
.PP
Operators of equal precedence are \fIalways\fR evaluated from left
to right, except where parentheses dictate otherwise.  This is important,
because the enhanced "+" and "\-" operators are not necessarily associative.
For example:
.PP
.nf
	1 + 2 + "string" + 3 + 4  yields "3string34"
	1 + (2 + "string") + (3 + 4)  yields "12string7"
	12:59 + 1 + "test"  yields "13:00test"
	12:59 + (1 + "test")  yields "12:591test"
.fi
.PP
The logical operators are \fInot\fR so-called short-circuit operators, as
they are in C.  Both operands are always evaluated.  Thus, an expression
such as:
.PP
.nf
	(f!=0) && (100/f <= 3)
.fi
.PP
will cause an error if f is zero.
.PP
.B VARIABLES
.PP
\fBRemind\fR allows you to assign values to variables.  The \fBSET\fR
command is used as follows:
.PP
\fBSET\fR \fIvar\fR \fIexpr\fR
.PP
\fIVar\fR is the name of a variable.  It must start with a letter or
underscore, and consist only of letters, digits and underscores.  Only
the first 12 characters of a variable name are significant.  Variable
names are \fInot\fR case sensitive; thus, "Afoo" and "afOo" are the same
variable.  Examples:
.PP
.nf
	SET a 10 + (9*8)
	SET b "This is a test"
	SET mydir getenv("HOME")
	SET time 12:15
	SET date today()
.fi
.PP
Note that variables themselves have no type.  They take on the type of
whatever you store in them.
.PP
To delete a variable, use the \fBUNSET\fR command:
.PP
\fBUNSET\fR \fIvar\fR [\fIvar\fR...]
.PP
For example, to delete all the variables declared above, use:
.PP
.nf
	UNSET a b mydir time date
.fi
.PP
.B SYSTEM VARIABLES
.PP
In addition to the regular user variables, \fBRemind\fR has several
"system variables" which are used to query or control the operating
state of \fBRemind\fR.  System variables are available starting from
version 03.00.07 of \fBRemind\fR.
.PP
All system variables begin with a dollar sign '$'.  They can be used
in \fBSET\fR commands and expressions just as regular variables can.
All system variables always hold values of a specified type.  In
addition, some system variables cannot be modified, and you cannot
create new system variables.  System variables can be initialized on
the command line with the \fB\-i\fR option, but you may need to quote
them to avoid having the shell interpret the dollar sign.  System
variable names are not case-sensitive.
.PP
The following system variables are defined.  Those marked
"read-only" cannot be changed with the \fBSET\fR command.
All system variables hold values of type \fBINT\fR, unless otherwise
specified.
.TP
.B $CalcUTC 
If 1 (the default), then \fBRemind\fR uses C library functions
to calculate the number of minutes between local and Universal Time
Coordinated.
This affects astronomical calculations (\fBsunrise()\fR for example.)
If 0, then you must supply the number of minutes between local and
Universal Time Coordinated in the \fB$MinsFromUTC\fR system variable.
.TP
.B $CalMode (read-only)
If non-zero, then the \fB\-c\fR option was supplied on the command line.
.TP
.B $Daemon (read-only)
If the daemon mode \fB\-z\fR was invoked, contains the number of
minutes between wakeups.  If not running in daemon mode, contains
0.  For the MS-DOS version, always contains 0.
.TP
.B $DefaultPrio
The default priority assigned to reminders without a \fBPRIORITY\fR
clause.  You can set this as required to adjust the priorities of
blocks of reminders without having to type priorities for individual
reminders.  At startup, \fB$DefaultPrio\fR is set to 5000; it can range
from 0 to 9999.
.TP
.B $DontFork (read-only)
If non-zero, then the \fB\-c\fR option was supplied on the command line.
For the MS-DOS version, always contains 1.
.TP
.B $DontTrigAts (read-only)
If non-zero, then the \fB\-a\fR option was supplied on the command line.
For the MS-DOS version, always contains 0.
.TP
.B $DontQueue (read-only)
If non-zero, then the \fB\-q\fR option was supplied on the command line.
For the MS-DOS version, always contains 1.
.TP
.B $EndSent (STRING type)
Contains a list of characters which end a sentence.  The \fBMSF\fR
keyword inserts two spaces after these characters.  Initially,
\fB$EndSent\fR is set to ".!?" (period, exclamation mark, and
question mark.)
.TP
.B $EndSentIg (STRING type)
Contains a list of characters which should be ignored when \fBMSF\fR
decides whether or not to place two spaces after a sentence.  Initially,
is set to "'>)]}"+CHAR(34) (single-quote, greater-than, right
parenthesis, right bracket, right brace, and double-quote.)
.PP
.RS
For example, the default values work as follows:
.PP
.nf
	MSF He said, "Huh! (Two spaces will follow this.)"  Yup.
.fi
.PP
because the final parenthesis and quote are ignored (for the purposes
of spacing) when they follow a period.
.RE
.TP
.B $FirstIndent
The number of spaces by which to indent the first line of a \fBMSF\fR-type
reminder.  The default is 0.
.TP
.B $FoldYear
The standard Unix library functions may have difficulty dealing with dates
later than 2037.  If this variable is set to 1, then the UTC calculations
"fold back" years later than 2037 before using the Unix library functions.
For example, to find out whether or not daylight savings time is in
effect in June, 2077, the year is "folded back" to 2010, because both
years begin on a Monday, and both are non-leapyears.  The rules for
daylight savings time are thus presumed to be identical for both
years, and the Unix library functions can handle 2010.  By default,
this variable is 0.  Set it to 1 if the sun or UTC functions misbehave
for years greater than 2037.
.TP
.B $FormWidth
The maximum width of each line of text for formatting \fBMSF\fR-type
reminders.  The default is 72.  If an \fBMSF\fR-type reminder contains
a word too long to fit in this width, it will not be truncated - the
width limit will be ignored.
.TP
.B $HushMode (read-only)
If non-zero, then the \fB\-h\fR option was supplied on the command line.
.TP
.B $IgnoreOnce (read-only)
If non-zero, then the \fB\-o\fR option was supplied on the command line,
or a date different from today's true date was supplied.  If non-zero,
then \fBONCE\fR directives will be ignored.
.TP
.B $InfDelta (read-only)
If non-zero, then the \fB\-t\fR option was supplied on the command line.
.TP
.B $LatDeg, $LatMin, $LatSec
These specify the latitude of your location.  \fB$LatDeg\fR can
range from -90 to 90, and the others from -59 to 59.  Northern latitudes
are positive; southern ones are negative.  For southern latitudes, all
three components should be negative.
.TP
.B $Location (STRING type)
This is a string specifying the name of your location.  It is usually
the name of your town or city.  It can be set to whatever you like,
but good style indicates that it should be kept consistent with
the latitude and longitude system variables.
.TP
.B $LongDeg, $LongMin, $LongSec
These specify the longitude of your location.  \fB$LongDeg\fR can
range from -180 to 180.  Western longitudes are positive; eastern
ones are negative.
.RS
.PP
The latitude and longitude information is required for the functions
\fBsunrise()\fR and \fBsunset()\fR.  Default values can be compiled
into \fBRemind\fR, or you can \fBSET\fR the correct values at the
start of your reminder scripts.
.RE
.TP
.B $MaxSatIter
The maximum number of iterations for the \fBSATISFY\fR clause
(described later.)  Must be at least 10.
.TP
.B $MinsFromUTC
The number of minutes between Universal Time Coordinated and local time.  If
\fB$CalcUTC\fR is non-zero, this is calculated upon startup of \fBRemind\fR.
Otherwise, you must set it explicitly.  If \fB$CalcUTC\fR is zero,
then \fB$MinsFromUTC\fR is used in the astronomical calculations.  You
must adjust it for daylight savings time yourself.  Also, if you
want to initialize \fB$MinsFromUTC\fR
using the \fB\-i\fR command-line option, you
must also set \fB$CalcUTC\fR to 0 with the \fB\-i\fR option.
.TP
.B $NextMode (read-only)
If non-zero, then the \fB\-n\fR option was supplied on the command line.
.TP
.B $NumQueued (read-only)
Contains the number of reminders queued so far for background
timed triggering.  For MS-DOS, always returns 0.
.TP
.B $NumTrig (read-only)
Contains the number of reminders triggered for the current date.  One
use for this variable is as follows:  Suppose you wish to shade in
the box of a PostScript calendar whenever a holiday is triggered.  You
could save the value of \fB$NumTrig\fR in a regular variable
prior to executing a block of
holiday reminders.  If the value of \fB$NumTrig\fR after the holiday
block is greater than the saved value, then at least one holiday
was triggered, and you can execute the command to shade in the
calendar box.  (See the section "Calendar Mode".)
.PP
.RS
Note that \fB$NumTrig\fR is affected \fIonly\fR
by \fBREM\fR commands; triggers in \fBIFTRIG\fR commands do
not affect it.  
.RE
.TP
.B $PSCal (read-only)
If non-zero, then the \fB\-p\fR option was supplied on the command line.
.TP
.B $RunOff (read-only)
If non-zero, the \fBRUN\fR directives are disabled.
.TP
.B $SimpleCal (read-only)
Set to a non-zero value if \fIeither\fR of the \fB\-p\fR or \fB\-s\fR
command-line options was supplied.
.TP
.B $SortByDate (read-only)
Set to 0 if no \fB\-g\fR option is used, 1 if sorting by date in ascending
order, or 2 if sorting by date in descending order.
.TP
.B $SortByPrio (read-only)
Set to 0 if no \fB\-g\fR option is used, 1 if sorting by priority in ascending
order, or 2 if sorting by priority in descending order.
.TP
.B $SortByTime (read-only)
Set to 0 if no \fB\-g\fR option is used, 1 if sorting by time in ascending
order, or 2 if sorting by time in descending order.
.TP
.B $SubsIndent
The number of spaces by which all lines (except the first) of an
\fBMSF\fR-type reminder should be indented.  The default is 0.
.PP
Note:  If any of the calendar modes are in effect, then the
values of $Daemon, $DontFork, $DontTrigAts, $DontQueue, $HushMode,
$IgnoreOnce, $InfDelta, and $NextMode are not meaningful.
.PP
.B BUILT-IN FUNCTIONS
.PP
\fBRemind\fR has a plethora of built-in functions.  The syntax for a function
call is the same as in C - the function name, followed a comma-separated list
of arguments in parentheses.  Function names are not case-sensitive.  If
a function takes no arguments, it must be followed by "()" in the function
call.  Otherwise, \fBRemind\fR will interpret it as a variable name,
and probably not work correctly.
.PP
In the descriptions below, short forms are used to denote acceptable
types for the arguments.  The characters "i", "s", "d" and "t" denote
\fBINT\fR, \fBSTRING\fR, \fBDATE\fR and \fBTIME\fR arguments,
respectively.  If an argument can be one of several types, the characters
are concatenated.  For example, "di_arg" denotes an argument which can be
a \fBDATE\fR or an \fBINT\fR.  "x_arg" denotes an argument which can be
of any type.  The type of the argument is followed by
an underscore and an identifier naming the argument, for convenience.
.PP
The built-in functions are:
.TP
.B abs(i_num)
Returns the absolute value of \fInum\fR.
.TP
.B access(s_file, si_mode)
Tests the access permissions for the file \fIfile\fR.  \fIMode\fR can
be a string, containing a mix of the characters "rwx" for read,
write and execute permission testing.  Alternatively, \fImode\fR can
be a number as described in the UNIX \fBaccess\fR(2) system call.  The
function returns 0 if the file can be accessed with the specified \fImode\fR,
and -1 otherwise.
.TP
.B args(s_fname)
Returns the number of arguments expected by the user-defined function
\fIfname\fR, or -1 if no such user-defined function exists.  Note that
this function examines only user-defined functions, not built-in functions.
Its main use is to determine whether or not a particular user-defined
function has been defined previously.  The \fBargs()\fR function is
available only in versions of \fBRemind\fR from 03.00.04 and up.
.TP
.B asc(s_string)
Returns an \fBINT\fR which is the ASCII code of the first character
in \fIstring\fR.  As a special case, \fBasc("")\fR returns 0.
.TP
.B baseyr()
Returns the "base year" which was compiled into \fBRemind\fR (normally
1990.)  All dates are stored internally as the number of days since
1 January of \fBbaseyr()\fR.
.TP
.B char(i_i1 [,i_i2...])
This function can take any number of \fBINT\fR arguments.  It returns
a \fBSTRING\fR consisting of the characters specified by the arguments.
Note that none of the arguments can be 0, unless there is only one
argument.  As a special case, \fBchar(0)\fR returns "".
.PP
.RS
Note that because \fBRemind\fR does not support escaping of characters
in strings, the only way to get a double-quote in a string is to use
\fBchar(34)\fR.  Yes, I know it's not portable - it assumes ASCII
coding.
.RE
.TP
.B choose(i_index, x_arg1 [,x_arg2...])
\fBChoose\fR must take at least two arguments, the first of which is
an \fBINT\fR.  If \fIindex\fR is \fIn\fR, then the \fIn\fRth subsequent
argument is returned.  If \fIindex\fR is less than 1, then \fIarg1\fR
is returned.  If \fIindex\fR is greater than the number of subsequent
arguments, then the last argument is returned.  Examples:
.PP
.nf
		\fBchoose(0, "foo", 1:13, 1000)\fR returns "foo"
		\fBchoose(1, "foo", 1:13, 1000)\fR returns "foo"
		\fBchoose(2, "foo", 1:13, 1000)\fR returns 1:13
		\fBchoose(3, "foo", 1:13, 1000)\fR returns 1000
		\fBchoose(4, "foo", 1:13, 1000)\fR returns 1000
.fi
.RS
Note that all arguments to \fBchoose()\fR are \fIalways\fR
evaluated.
.RE
.TP
.B coerce(s_type, x_arg)
This function converts \fIarg\fR to the specified \fItype\fR, if such
conversion is possible.  \fIType\fR must be one of "INT", "STRING",
"DATE" or "TIME" (case-insensitive).
The conversion rules are as follows:
.RS
.PP
If \fIarg\fR is already of the \fItype\fR specified, it is returned
unchanged.
.PP
If \fItype\fR is "STRING", then \fIarg\fR is converted to a string
consisting of its printed representation.
.PP
If \fItype\fR is "DATE", then an \fBINT\fR \fIarg\fR is converted
by interpreting it as the number of days since 1 January \fBbaseyr()\fR.
A \fBSTRING\fR \fIarg\fR is converted by attempting to read it as if
it were a printed date.  A \fBTIME\fR \fIarg\fR cannot be converted to
a date.
.PP
If \fItype\fR is "TIME", then an \fBINT\fR \fIarg\fR is converted
by interpreting it as the number of minutes since midnight.
A \fBSTRING\fR \fIarg\fR is converted by attempting to read it as if
it were a printed time.  A \fBDATE\fR \fIarg\fR cannot be converted to
a time.
.PP
If \fItype\fR is "INT", then \fBDATE\fR and \fBTIME\fR arguments are
converted using the reverse of procedures described above.  A
\fBSTRING\fR \fIarg\fR is converted by parsing it as an integer.
.RE
.TP
.B date(i_y, i_m, i_d)
The \fBdate()\fR function returns a \fBDATE\fR object with the year,
month and day components specified by \fIy\fR, \fIm\fR and \fId\fR.
.TP
.B day(d_date)
This function takes a \fBDATE\fR as an argument, and returns an \fBINT\fR
which is the day-of-month component of \fIdate\fR.
.TP
.B daysinmon(i_m, i_y)
Returns the number of days in month \fIm\fR (1-12) of the year \fIy\fR.
.TP
.B defined(s_var)
Returns 1 if the variable named by \fIvar\fR is defined, or 0 if it is not.
.RS
Note that \fBdefined()\fR takes a \fBSTRING\fR argument; thus, to check
if variable X is defined, use:
.PP
.nf
		defined("X")
.fi
.PP
and not:
.PP
.nf
		defined(X)
.fi
.PP
The second example will attempt to evaluate X, and will return an
error if it is undefined or not of type \fBSTRING\fR.
.RE
.TP
.B dosubst(s_str [,d_date [,t_time]])
Returns a \fBSTRING\fR which is the result of passing \fIstr\fR through
the substitution filter described earlier.  The parameters \fIdate\fR
and \fItime\fR establish the effective trigger date and time used by the
substitution filter.  If \fIdate\fR and \fItime\fR are omitted, they
default to \fBtoday()\fR and \fBnow()\fR.
.RS
.PP
Note that if \fIstr\fR does not end with "%", a newline character will be
added to the end of the result.  Also, calling \fBdosubst()\fR with a
\fIdate\fR which is in the past (i.e., if \fIdate\fR < \fBtoday()\fR)
will produce undefined results.
.PP
\fBDosubst()\fR is only available starting from version 03.00.04 of
\fBRemind\fR.
.RE
.TP
.B easterdate(di_arg)
If \fIarg\fR is an \fBINT\fR, then returns the date of Easter Sunday
for the specified year.  If \fIarg\fR is a \fBDATE\fR, then returns the
date of the next Easter Sunday on or after \fIarg\fR.
.TP
.B filedate(s_filename)
Returns the modification date of \fIfilename\fR.  If \fIfilename\fR
does not exist, or its modification date is before the year
\fBbaseyr()\fR, then 1 January of \fBbaseyr()\fR is returned.
.TP
.B filedir()
Returns the directory which contains the current file being
processed.  It may be a relative or absolute pathname, but
is guaranteed to be correct for use in an \fBINCLUDE\fR command as
follows:
.PP
.nf
		INCLUDE [filedir()]/stuff
.fi
.PP
.RS
This includes the file "stuff" in the same directory as the
current file being processed.
.RE
.TP
.B filename()
Returns (as a \fBSTRING\fR) the name of the current file being processed
by \fBRemind\fR.  Inside included files, returns the name of the
included file.
.TP
.B getenv(s_envvar)
Similar to the \fBgetenv\fR(2) system call.  Returns a string representing
the value of the specified environment variable.  Returns "" if the
environment variable is not defined.  Note that the names of environment
variables are generally case-sensitive; thus, getenv("HOME") is not
the same as getenv("home").
.TP
.B hour(t_time)
Returns the hour component of \fItime\fR.
.TP
.B iif(si_test1, x_arg1, [si_test2, x_arg2,...], x_default)
If \fItest1\fR is not zero or the null string, returns \fIarg1\fR.
Otherwise, if \fItest2\fR is not zero or the null string, returns
\fIarg2\fR, and so on.  If all of the \fItest\fR arguments are false,
returns \fIdefault\fR.  Note that all arguments are \fIalways\fR evaluated.
This function accepts an odd number of arguments - note that prior to version
03.00.05 of \fBRemind\fR, it accepted 3 arguments only.  The 3-argument
version of \fBiif()\fR is compatible with previous versions of \fBRemind\fR.
.TP
.B index(s_search, s_target [,i_start)
Returns an \fBINT\fR which is the location of \fItarget\fR in the
string \fIsearch\fR.  The first character of a string is numbered 1.
If \fItarget\fR does not exist in \fIsearch\fR, then 0 is returned.
.RS
.PP
The optional parameter \fIstart\fR specifies the position in
\fIsearch\fR at which to start looking for \fItarget\fR.
.RE
.TP
.B isdst([d_date [,t_time]])
Returns a positive number if daylight savings time is in
effect on the specified date and time.  \fIDate\fR
defaults to \fBtoday()\fR and \fItime\fR defaults to midnight.
.RS
.PP
Note that this function is only as reliable as the C run-time library
functions.  It is available starting with version 03.00.07 of \fBRemind\fR.
.RE
.TP
.B isleap(id_arg)
Returns 1 if \fIarg\fR is a leap year, and 0 otherwise.  \fIArg\fR can
be either an \fBINT\fR or a \fBDATE\fR object.  If a \fBDATE\fR is
supplied, then the year component is used in the test.
.TP
.B isomitted(d_date)
Returns 1 if \fIdate\fR is omitted, given the current global \fBOMIT\fR
context.  Returns 0 otherwise.
.TP
.B hebdate(i_day, s_hebmon [,id_yrstart [,i_jahr [,i_aflag]]])
Support for Hebrew dates - see the section "The Hebrew Calendar"
.TP
.B hebday(d_date)
Support for Hebrew dates - see the section "The Hebrew Calendar"
.TP
.B hebmon(d_date)
Support for Hebrew dates - see the section "The Hebrew Calendar"
.TP
.B hebyear(d_date)
Support for Hebrew dates - see the section "The Hebrew Calendar"
.TP
.B language()
Returns a \fBSTRING\fR naming the language supported by \fBRemind\fR.
(See "Foreign Language Support.") By default, \fBRemind\fR is compiled
to support English messages, so this function returns "English".  For
other languages, this function will return the English name of the
language (e.g. "German") Note that \fBlanguage()\fR is not available
in versions of \fBRemind\fR prior to 03.00.02.
.TP
.B lower(s_string)
Returns a \fBSTRING\fR with all upper-case characters in \fIstring\fR
converted to lower-case.
.TP
.B max(x_arg1 [,x_arg2...)
Can take any number of arguments, and returns the maximum.  The arguments
can be of any type, but must all be of the same type.  They are compared
as with the > operator.
.TP
.B min(x_arg1 [,x_arg2...)
Can take any number of arguments, and returns the minimum.  The arguments
can be of any type, but must all be of the same type.  They are compared
as with the < operator.
.TP
.B minsfromutc([d_date [,t_time]])
Returns the number of minutes from Universal Time Coordinated 
(formerly GMT) to
local time on the specified date and time.  \fIDate\fR defaults to
\fBtoday()\fR and \fItime\fR defaults to midnight.  If local time
is before UTC, the result is negative.  Otherwise, the result is
positive.
.RS
.PP
Note that this function is only as reliable as the C run-time library
functions.  It is available starting with version 03.00.07 of \fBRemind\fR.
.RE
.TP
.B minute(t_time)
Returns the minute component of \fItime\fR.
.TP
.B mon(di_arg)
If \fIarg\fR is of \fBDATE\fR type, returns a string which names the month
component of the date.  If \fIarg\fR is an \fBINT\fR from 1 to
12, returns a string which names the month.
.TP
.B monnum(d_date)
Returns an \fBINT\fR from 1 to 12, representing the month component of
\fIdate\fR.
.TP
.B "moondate(i_phase [,d_date [,t_time]])"
This function returns the date of the first occurrence of the phase
\fIphase\fR of the moon on or after \fIdate\fR and \fItime\fR.
\fIPhase\fR can range from 0 to 3, with 0 signifying new moon, 1 first
quarter, 2 full moon, and 3 third quarter.  If \fIdate\fR is omitted,
it defaults to \fBtoday()\fR.  If \fItime\fR is omitted, it defaults
to midnight.
.RS
.PP
For example, the following returns the date of the next full moon:
.PP
.nf
		SET fullmoon moondate(2)
.fi
.PP
.RE
.TP
.B "moontime(i_phase [,d_date [,t_time]])"
This function returns the time of the first occurrence of the phase
\fIphase\fR of the moon on or after \fIdate\fR and \fItime\fR.
\fIPhase\fR can range from 0 to 3, with 0 signifying new moon, 1 first
quarter, 2 full moon, and 3 third quarter.  If \fIdate\fR is omitted,
it defaults to \fBtoday()\fR.  If \fItime\fR is omitted, it defaults
to midnight.  \fBMoontime()\fR is intended to be used in conjunction
with \fBmoondate()\fR.  The \fBmoondate()\fR and \fBmoontime()\fR
functions are accurate to within a couple of minutes of the
times in "Old Farmer's Almanac" for Ottawa, Ontario.
.RS
.PP
For example, the following returns the date and time of the next full moon:
.PP
.nf
		MSG Next full moon at [moontime(2)] on [moondate(2)]
.fi
.PP
.RE
.TP
.B moonphase([d_date [,t_time]])
This function returns the phase of the moon on \fIdate\fR and \fItime\fR,
which default to \fBtoday()\fR and midnight, respectively.  The returned
value is an integer from 0 to 359, representing the phase of the moon
in degrees.  0 is a new moon, 180 is a full moon, 90 is first-quarter, etc.
.TP
.B now()
Returns the current system time, as a \fBTIME\fR type.  This may be
the actual time, or a time supplied on the command line.
.TP
.B ord(i_num)
Returns a string which is the ordinal number \fInum\fR.  For example,
\fBord(2)\fR returns "2nd", and \fBord(213)\fR returns "213th".
.TP
.B ostype()
Returns "UNIX" on UNIX systems, "MSDOS" on MS-DOS systems, and "OS/2"
on OS/2 systems.  If you run \fBRemind\fR in an MS-DOS box under OS/2,
this function returns "MSDOS".
.TP
.B plural(i_num [,s_str1 [,s_str2]])
Can take from one to three arguments.  If one argument is supplied, returns
"s" if \fInum\fR is not 1, and "" if \fInum\fR is 1.
.RS
.PP
If two arguments are supplied, returns \fIstr1\fR + "s" if \fInum\fR is
not 1.  Otherwise, returns \fIstr1\fR.
.PP
If three arguments are supplied, returns \fIstr1\fR if \fInum\fR is 1, and
\fIstr2\fR otherwise.
.RE
.TP
.B psmoon(i_phase [,i_size [,s_note [,i_notesize]]])
Returns a \fBSTRING\fR consisting of PostScript code to draw a moon in
the upper-left hand corner of the calendar box.  \fIPhase\fR specifies
the phase of the moon, and is 0 (new moon), 1 (first quarter), 2 (full
moon) or 3 (third quarter).  If \fIsize\fR is specified, it controls
the radius of the moon in PostScript units (1/72 inch.)  If it is not
specified or is negative, the size of the day-number font is used.
.PP
.PP
.RS
For example, the following four lines place moon symbols on the PostScript
calendar:
.PP
.nf
		REM [trigger(moondate(0))] PS [psmoon(0)]
		REM [trigger(moondate(1))] PS [psmoon(1)]
		REM [trigger(moondate(2))] PS [psmoon(2)]
		REM [trigger(moondate(3))] PS [psmoon(3)]
.fi
.PP
If \fInote\fR is specified, the text is used to annotate the moon
display.  The font is the same font used for calendar entries.  If
\fInotesize\fR is given, it specifies the font size to use for the
annotation, in PostScript units (1/72 inch.)  If \fInotesize\fR is not
given, it defaults to the size used for calendar entries.  (If you annotate
the display, be careful not to overwrite the day number -- \fBRemind\fR
does not check for this.)  For example, if you want the time of each new
moon displayed, you could use this in your reminder script:
.PP
.nf
	REM [trigger(moondate(0))] PS [psmoon(0, -1, moontime(0)+"")]
.fi
.PP
Note how the time is coerced to a string by concatenating the null string.
.RE
.TP
\fBpsshade(i_gray)\fR or \fBpsshade(i_red, i_green, i_blue)\fR
Returns a \fBSTRING\fR which consists of PostScript commands to
shade a calendar box.  \fINum\fR can range from 0 (completely black)
to 100 (completely white.)  If three arguments are given, they specify
red, green and blue intensity from 0 to 100.  
Here's an example of how to use this:
.RS
.PP
.nf
		REM Sat Sun PS [psshade(95)]
.fi
.PP
The above command emits PostScript code to lightly shade the boxes
for Saturday and Sunday in a PostScript calendar.
.RE
.TP
.B realnow()
Returns the true time of day as provided by the operating system.
This is in contrast to \fBnow()\fR, which may return a time supplied
on the command line.
.TP
.B realtoday()
Returns the date as provided by the operating system.  This is in contrast to
\fBRemind\fR's concept of "today", which may be changed if it is running
in calendar mode, or if a date has been supplied on the command line.
.TP
.B sgn(i_num)
Returns -1 if \fInum\fR is negative, 1 if \fInum\fR is positive,
and 0 if \fInum\fR is zero.
.TP
.B shell(s_cmd)
Executes \fIcmd\fR as a system command, and returns the first 511
characters of output resulting from \fIcmd\fR.  Any whitespace
character in the output is converted to a space.  Note that if \fBRUN
OFF\fR has been executed, or the \fB\-r\fR command-line option has
been used, \fBshell()\fR will result in an error, and \fIcmd\fR will
not be executed.
.TP
.B strlen(s_str)
Returns the length of \fIstr\fR.
.TP
.B substr(s_str, i_start [,i_end])
Returns a \fBSTRING\fR consisting of all characters in \fIstr\fR from
\fIstart\fR up to and including \fIend\fR.  Characters are numbered
from 1.  If \fIend\fR is not supplied, then it defaults to the length
of \fIstr\fR.
.TP
.B sunrise([d_date])
Returns a \fBTIME\fR indicating the time of sunrise on the specified
\fIdate\fR (default \fBtoday()\fR.)  In high lattitudes, there
may be no sunrise on a particular day, in which case \fBsunrise()\fR
returns the \fBINT\fR 0 if the sun never sets, or 1440 if it never rises.
.TP
.B sunset([d_date])
Returns a \fBTIME\fR indicating the time of sunset on the specified
\fIdate\fR (default \fBtoday()\fR.)  In high lattitudes, there
may be no sunset on a particular day, in which case \fBsunset()\fR
returns the \fBINT\fR 0 if the sun never rises, or 1440 if it never
sets.
.RS
.PP
The functions \fBsunrise()\fR and \fBsunset()\fR are based on
an algorithm in "Almanac for Computers for the year 1978" by
L. E. Doggett, Nautical Almanac Office, USNO.  They require
the latitude and longitude to be specified by setting the appropriate
system variables.  (See "System Variables".)  The sun functions
should be accurate to within about 2 minutes for latitudes lower
than 60 degrees.  The functions are available starting from version
03.00.07 of \fBRemind\fR.
.RE
.TP
.B time(i_hr, i_min)
Creates a \fBTIME\fR with the hour and minute components specified by
\fIhr\fR and \fImin\fR.
.TP
.B today()
Returns \fBRemind\fR's notion of "today."  This may be the actual system
date, or a date supplied on the command line, or the date of the
calendar entry currently being computed.
.TP
.B trigdate()
Returns the calculated trigger date of the last \fBREM\fR
or \fBIFTRIG\fR command.  If used
in the \fIbody\fR of a \fBREM\fR command, returns that command's trigger date.
.TP
.B trigger(d_date [,t_time [,i_utcflag]])
Returns a string suitable for use in a \fBREM\fR command, allowing you
to calculate trigger dates in advance.  (See the section "Expression
pasting" for more information.)  Note that \fBtrigger()\fR
\fIalways\fR returns its result in English, even for foreign-language
versions of \fBRemind\fR.  This is to avoid problems with certain C
libraries which do not handle accented characters properly.  Normally,
the \fIdate\fR and \fItime\fR are the local date and time; however, if
\fIutcflag\fR is non-zero, the \fIdate\fR and \fItime\fR are
interpreted as UTC times, and are converted to local time.  Examples:
.RS
.PP
trigger('1993/04/01')
.PP
returns "1 April 1993",
.PP
trigger('1994/08/09', 12:33)
.PP
returns "9 August 1994 AT 12:33", and
.PP
trigger('1994/12/01', 03:00, 1)
.PP
returns "30 November 1994 AT 22:00" for EST, which is 5 hours behind UTC.
The value for your time zone may differ.
.RE
.TP
.B trigtime()
Returns the time of the last \fBREM\fR command with an \fBAT\fR clause.
.TP
.B trigvalid()
Returns 1 if the value returned by \fBtrigdate()\fR is valid for the most
recent \fBREM\fR command, or 0 otherwise.  Sometimes \fBREM\fR commands
cannot calculate a trigger date.  For example, the following \fBREM\fR
command can never be triggered:
.PP
.nf
		REM Mon OMIT Mon SKIP MSG Impossible!
.fi
.PP
.TP
.B typeof(x_arg)
Returns "STRING", "INT", "DATE" or "TIME", depending on the type of \fIarg\fR.
.TP
.B upper(s_string)
Returns a \fBSTRING\fR with all lower-case characters in \fIstring\fR
converted to upper-case.
.TP
.B value(s_varname [,x_default])
Returns the value of the specified variable.  For example, value("X"+"Y")
returns the value of variable XY, if it is defined.  If XY is not defined,
an error results.
.RS
.PP
However, if you supply a second argument, it is returned if the \fIvarname\fR
is not defined.  The expression value("XY", 0) will return 0 if XY is not
defined, and the value of XY if it is defined.
.RE
.TP
.B version()
Returns a string specifying the version of \fBRemind\fR.  For version 
03.00.04, returns "03.00.04".  It is guaranteed that as new versions of
\fBRemind\fR are released, the value returned by \fBversion()\fR will
strictly increase, according to the rules for string ordering.
.TP
.B wkday(di_arg)
If \fIarg\fR is a \fBDATE\fR, returns a string representing the day of the
week of the date.  If \fIarg\fR is an \fBINT\fR from 0 to 6, returns
the corresponding weekday ("Sunday" to "Saturday").
.TP
.B wkdaynum(d_date)
Returns a number from 0 to 6 representing the day-of-week of the specified
\fIdate\fR.  (0 represents Sunday, and 6 represents Saturday.)
.TP
.B year(d_date)
Returns a \fBINT\fR which is the year component of \fIdate\fR.
.SH EXPRESSION PASTING
.PP
An extremely powerful feature of \fBRemind\fR is its macro capability,
or "expression pasting."
.PP
In almost any situation where \fBRemind\fR is not expecting an expression,
you can "paste" an expression in.  To do this, surround the expression
with square brackets.  For example:
.PP
.nf
	REM [trigger(mydate)] MSG foo
.fi
.PP
This evaluates the expression "trigger(mydate)", where "mydate" is
presumably some pre-computed variable, and then "pastes" the result
into the command-line for the parser to process.
.PP
A formal description of this is:  When \fBRemind\fR encounters a
"pasted-in" expression, it evaluates the expression, and coerces the
result to a \fBSTRING\fR.  It then substitutes the string for the
pasted-in expression, and continues parsing.  Note, however, that
expressions are evaluated only once, not recursively.  Thus, writing:
.PP
.nf
	["[a+b]"]
.fi
.PP
causes \fBRemind\fR to read the token "[a+b]".  It does not interpret
this as a pasted-in expression.  In fact, the only way to get a literal
left-bracket into a reminder is to use ["["].
.PP
You can use expression pasting almost anywhere.  However, there are a few
exceptions:
.TP
o
If \fBRemind\fR is expecting an expression, as in the \fBSET\fR command,
or the \fBIF\fR command, then no expression pasting takes place.  The
expression is simply evaluated as if the square brackets were not there.
.TP
o
You cannot use expression pasting for the first token on a line.
For example, the following will not work:
.PP
.nf
		["SET"] a 1
.fi
.RS
.PP
This restriction is because \fBRemind\fR must be able to unambiguously
determine the first token of a line for the flow-control commands (to
be discussed later.)
.PP
In fact, if \fBRemind\fR cannot determine the first token on a line, it
assumes that it is a \fBREM\fR command.  If expression-pasting is used,
\fBRemind\fR assumes it is a \fBREM\fR command.  Thus, the following
three commands are equivalent:
.PP
.nf
		REM 12 Nov 1993 AT 13:05 MSG BOO!
		12 Nov 1993 AT 13:05 MSG BOO!
		[12] ["Nov " + 1993] AT [12:05+60] MSG BOO!
.fi
.RE
.TP
o
You cannot use expression-pasting to determine the type (\fBMSG\fR,
\fBCAL\fR, etc.) of a \fBREM\fR command.  You can paste expressions
before and after the \fBMSG\fR, etc keywords, but cannot do something like
this:
.PP
.nf
		REM ["12 Nov 1993 AT 13:05 " + "MSG" + " BOO!"]
.fi
.PP
.B COMMON PITFALLS IN EXPRESSION PASTING
.PP
Remember, when pasting in expressions, that extra spaces are not
inserted.  Thus, something like:
.PP
.nf
	REM[expr]MSG[expr]
.fi
.PP
will probably fail.
.PP
If you use an expression to calculate a \fIdelta\fR or \fIback\fR,
ensure that the result is a positive number.  Something like:
.PP
.nf
	REM +[mydelta] Nov 12 1993 MSG foo
.fi
.PP
will fail if \fImydelta\fR happens to be negative.
.PP
.SH FLOW CONTROL COMMANDS
.PP
\fBRemind\fR has commands which control the flow of a reminder script.
Normally, reminder scripts are processed sequentially.  However,
\fBIF\fR and related commands allow you to process files conditionally,
and skip sections which you don't want interpreted.
.PP
.B THE IF COMMAND
.PP
The \fBIF\fR command has the following form:
.PP
.nf
	IF expr
		t-command
		t-command...
	ELSE
		f-command
		f-command...
	ENDIF
.fi
.PP
Note that the commands are shown indented for clarity.  Also, the \fBELSE\fR
portion can be omitted.  \fBIF\fR commands can be nested up to a small limit,
probably around 8 or 16 levels of nesting, depending on your system.
.PP
If the \fIexpr\fR evaluates to a non-zero \fBINT\fR, or a non-null
\fBSTRING\fR, then the \fBIF\fR portion is considered true, and the
\fIt-commands\fR are executed.  If \fIexpr\fR evaluates to zero or
null, then the \fIf-commands\fR (if the \fBELSE\fR portion is present)
are executed.  If \fIexpr\fR is not of type \fBINT\fR or \fBSTRING\fR,
then it is an error.
.PP
Examples:
.PP
.nf
	IF defined("want_hols")
		INCLUDE /usr/share/remind/holidays
	ENDIF

	IF today() > '1992/2/10'
		set missed_ap "You missed it!"
	ELSE
		set missed_ap "Still have time..."
	ENDIF
.fi
.PP
.B THE IFTRIG COMMAND
.PP
The \fBIFTRIG\fR command is similar to an \fBIF\fR command, except
that it computes a trigger (as in the \fBREM\fR command), and evaluates
to true if a corresponding \fBREM\fR command would trigger.  Examples:
.PP
.nf
	IFTRIG 1 Nov
		; Executed on 1 Nov
	ELSE
		; Executed except on 1 Nov
	ENDIF

	IFTRIG 1 -1 OMIT Sat Sun +4
		; Executed on last working day of month,
		; and the 4 working days preceding it
	ELSE
		; Executed except on above days
	ENDIF
.fi
.PP
Note that the \fBIFTRIG\fR command computes a trigger date, which can
be retrieved with the \fBtrigdate()\fR function.  You can use all of
the normal trigger components, such as \fBUNTIL\fR, \fIdelta\fR, etc in the
\fBIFTRIG\fR command.
.PP
.SH USER-DEFINED FUNCTIONS
.PP
In addition to the built-in functions, \fBRemind\fR allows you to define
your own functions.  The \fBFSET\fR command does this for you:
.PP
\fBFSET\fR \fIfname\fR(\fIargs\fR) \fIexpr\fR
.PP
\fIFname\fR is the name of the function, and follows the convention for
naming variables.  \fIArgs\fR is a comma-separated list of arguments, and
\fIexpr\fR is an expression.  \fIArgs\fR can be empty, in which case
you define a function taking no parameters.  Here are some examples:
.PP
.nf
	FSET double(x) 2*x
	FSET yeardiff(date1, date2) year(date1) - year(date2)
	FSET since(x) ord(year(trigdate())-x)
.fi
.PP
The last function is useful in birthday reminders.  For example:
.PP
.nf
	REM 1 Nov +12 MSG Dean's [since(1984)] birthday is %b.
.fi
.PP
Dean was born in 1984.  The above example, on 1 November 1992, would print:
.PP
.nf
	Dean's 8th birthday is today.
.fi
.PP
Notes:
.TP
o
If you access a variable in \fIexpr\fR which is not in the list of arguments,
the "global" value (if any) is used.
.TP
o
Function and parameter names are significant only to 12 characters.
.TP
o
The \fBvalue()\fR function \fIalways\fR accesses the "global" value of a
variable, even if it has the same name as an argument.  For example:
.RS
.PP
.nf
		fset func(x) value("x")
		set x 1
		set y func(5)
.fi
.PP
The above sequence sets y to 1, which is the global value of x.
.RE
.TP
o
User-defined functions may call other functions, including other user-defined
functions.  However, recursive calls are not allowed.
.TP
o
User-defined functions are not syntax-checked when they are defined; parsing
occurs only when they are called.
.TP
o
If a user-defined function has the same name as a built-in function,
it is ignored and the built-in function is used.  To prevent conflicts
with future versions of \fBRemind\fR (which may define more built-in
functions), you may wish to name all user-defined functions beginning
with an underscore.
.PP
.SH PRECISE SCHEDULING
.PP
The \fBWARN\fR keyword allows precise control over advance warning in
a more flexible manner than the \fIdelta\fR mechanism.  It should be
followed by the name of a user-defined function, \fIwarn_function\fR.
.PP
If a \fIwarn_function\fR is supplied, then it must take one argument of
type \fBINT\fR.  \fBRemind\fR ignores any delta, and instead calls
\fIwarn_function\fR successively with the arguments 1, 2, 3, ...
.PP
\fIWarn_function\fR's return value \fIn\fR is interpreted as follows:
.TP
o
If \fIn\fR is positive, then the reminder is triggered exactly \fIn\fR
days before its trigger date.
.TP
o
If \fIn\fR is negative, then it is triggered \fIn\fR days before its
trigger date, \fInot counting\fR \fBOMIT\fRted days.
.PP
As an example, suppose you wish to be warned of American Independence Day
5, 3, and 1 days in advance.  You could use this:
.PP
.nf
	FSET _wfun(x) choose(x, 5, 3, 1, 0)
	REM 4 July WARN _wfun MSG American Independence Day is %b.
.fi
.PP
.B NOTES
.TP
1
If an error occurs during the evaluation of \fIwarn_function\fR, then
\fBRemind\fR stops calling it and simply issues the reminder on its
trigger date.
.TP
2
If the absolute-values of the return values of \fIwarn_function\fR are
not monotonically decreasing, \fBRemind\fR stops calling it and issues
the reminder on its trigger date.
.TP
3
\fIWarn_function\fR should (as a matter of good style) return 0 as the
final value in its sequence of return values.  However, a reminder will
\fIalways\fR be triggered on its trigger date, regardless of what
\fIwarn_function\fR does.
.PP
Similarly to \fBWARN\fR, the \fBSCHED\fR keyword allows precise
control over the scheduling of timed
reminders.  It should be followed by the name of a user-defined function,
\fIsched_function\fR.
.PP
If a scheduling function is supplied, then it must take one argument of
type \fBINT\fR.  Rather than using the \fBAT\fR time, time \fIdelta\fR, and
time \fIrepeat\fR, \fBRemind\fR calls the scheduling function to determine
when to trigger the reminder.  The first time the reminder is queued, the
scheduling function is called with an argument of 1.  Each time the reminder
is triggered, it is re-scheduled by calling the scheduling function again.
On each call, the argument is incremented by one.
.PP
The return value of the scheduling function must be an \fBINT\fR or a
\fBTIME\fR.  If the return value is a \fBTIME\fR, then the reminder is
re-queued to trigger at that time.  If it is a positive integer \fIn\fR,
then the reminder is re-queued to trigger at the previous trigger time
plus \fIn\fR minutes.  Finally, if it is a negative integer or zero, then
the reminder is re-queued to trigger \fIn\fR minutes before the \fBAT\fR
time.  Note that there must be an \fBAT\fR clause for the \fBSCHED\fR
clause to do anything.
.PP
Here's an example:
.PP
.nf
	FSET _sfun(x) choose(x, -60, 30, 15, 10, 3, 1, 1, 1, 1, 0)
	REM AT 13:00 SCHED _sfun MSG foo
.fi
.PP
The reminder would first be triggered at 13:00-60 minutes, or at 12:00.
It would next be triggered 30 minutes later, at 12:30.  Then, it would
be triggered at 12:45, 12:55, 12:58, 12:59, 13:00, 13:01 and 13:02.
.PP
.B NOTES
.TP
1
If an error occurs during the evaluation of \fIsched_func\fR, then
\fBRemind\fR reverts to using the \fBAT\fR time and the \fIdelta\fR
and \fIrepeat\fR values, and never calls \fIsched_func\fR again.
.TP
2
If processing \fIsched_func\fR yields a time earlier than the current
system time, it is repeatedly called with increasing argument until it
yields a value greater than or equal to the current time.  However, if
the sequence of values calculated during the repetition is not strictly
increasing, then \fBRemind\fR reverts to the default behaviour and
never calls \fIsched_func\fR again.
.TP
3
It is quite possible using \fIsched_func\fR to keep triggering a reminder
even after the \fBAT\fR-time.  However, it is not possible to reschedule
a reminder past midnight \- no crossing of date boundaries is allowed.
Also, it is quite possible to \fBnot\fR trigger a reminder on the \fBAT\fR
time when you use a scheduling function.  However, if your scheduling
function is terminated (for reasons 1 and 2) before the \fBAT\fR time of
the reminder, it \fIwill\fR be triggered at the \fBAT\fR time, because
normal processing takes over.
.TP
4
Your scheduling functions should (as a matter of good style) return
0 when no more scheduling is required.  See the example.
.TP
5
All scheduling functions are evaluated \fIafter\fR the entire Remind
script has been read in.  So whatever function definitions are in effect
at the end of the script are used.
.PP
.SH THE SATISFY CLAUSE
.PP
The form of \fBREM\fR which uses \fBSATISFY\fR is as follows:
.PP
\fBREM\fR \fItrigger\fR \fBSATISFY\fR \fIexpr\fR
.PP
The way this works is as follows:  \fBRemind\fR first calculates a trigger
date, in the normal fashion.  Next, it sets \fBtrigdate()\fR to the
calculated trigger date.  It then evaluates \fIexpr\fR.  If the result
is not the null string or zero, processing
ends.  Otherwise, \fBRemind\fR computes the next trigger date, and re-tests
\fIexpr\fR.  This iteration continues until \fIexpr\fR evaluates to non-zero
or non-null, or until the iteration limit specified with the \fB\-x\fR
command-line option is reached.
.PP
If \fIexpr\fR is not satisfied, then \fBtrigvalid()\fR is set to 0.
Otherwise, \fBtrigvalid()\fR is set to 1.  In any event, no error message
is issued.
.PP
This is really useful only if \fIexpr\fR involves a call to the
\fBtrigdate()\fR function; otherwise, \fIexpr\fR will not change as
\fBRemind\fR iterates.
.PP
An example of the usefulness of \fBSATISFY\fR:  Suppose you wish to
be warned of every Friday the 13th.  Your first attempt may be:
.PP
.nf
	# WRONG!
	REM Fri 13 +2 MSG Friday the 13th is %b.
.fi
.PP
But this won't work.  This reminder triggers on the first Friday
on or after the 13th of each month.  The way to do it is with a
more complicated sequence:
.PP
.nf
	REM 13 SATISFY wkdaynum(trigdate()) == 5
	IF trigvalid()
		REM [trigger(trigdate())] +2 MSG \\
		Friday the 13th is %b.
	ENDIF
.fi
.PP
Let's see how this works.  The \fBSATISFY\fR clause iterates through
all the 13ths of successive months, until a trigger date is found whose
day-of-week is Friday (== 5).  If a valid date was found, we use the
calculated trigger date (converted into a trigger format with the
\fBtrigger()\fR function) to set up the next reminder.
.PP
We could also have written:
.PP
.nf
	REM Fri SATISFY day(trigdate()) == 13
.fi
.PP
but this would result in more iterations, since "Fridays" occur more
often than "13ths of the month."
.PP
This technique of using one \fBREM\fR command to calculate a trigger date
to be used by another command is quite powerful.  For example, suppose
you wanted to OMIT Labour day, which is the first Monday in September.  You
could use:
.PP
.nf
	# Note: SATISFY 1 is an idiom for "do nothing"
	REM Mon 1 Sept SATISFY 1
	OMIT [trigger(trigdate())]
.fi
.PP
\fBCAVEAT:\fR This \fIonly\fR omits the \fInext\fR Labour Day, not
all Labour Days in the future.  This could cause strange results, as
the \fBOMIT\fR context can change depending on the current date.  For
example, if you use the following command after the above commands:
.PP
.nf
	REM Mon AFTER msg hello
.fi
.PP
the result will not be as you expect.  Consider producing a calendar
for September, 1992.  Labour Day was on Monday, 7 September, 1992.
However, when \fBRemind\fR gets around to calculating the trigger
for Tuesday, 8 September, 1992, the \fBOMIT\fR command will now be
omitting Labour Day for 1993, and the "Mon AFTER" command
will not be triggered.  (But see the description of \fBSCANFROM\fR
in the section "Details about Trigger Computation.")
.PP
It is probably best to stay away from computing \fBOMIT\fR
trigger dates unless you keep these pitfalls in mind.
.PP
For versions of \fBRemind\fR starting from 03.00.07, you can include
a \fBMSG\fR, \fBRUN\fR, etc. clause in a \fBSATISFY\fR clause as
follows:
.PP
.nf
	REM trigger_stuff SATISFY [expr] MSG body
.fi
.PP
Note that for this case only, the \fIexpr\fR after \fBSATISFY\fR
\fImust\fR be enclosed in braces.  It must come after all the other
components of the trigger, and immediately before the \fBMSG\fR,
\fBRUN\fR, etc. keyword.  If \fIexpr\fR cannot be satisfied, then
the reminder is not triggered.
.PP
Thus, the "Friday the 13th" example can be expressed more compactly as:
.PP
.nf
	REM 13 +2 SATISFY [wkdaynum(trigdate()) == 5] \\
		MSG Friday the 13th is %b.
.fi
.PP
And you can trigger a reminder on Mondays, Wednesdays and Thursdays
occurring on odd-numbered days of the month with the following:
.PP
.nf
	REM Mon Wed Thu SATISFY [day(trigdate())%2] \\
		MSG Here it is!!!
.fi
.PP
.SH DEBUGGING REMINDER SCRIPTS
.PP
Although the command-line \fB\-d\fR option is useful for debugging, it
is often overkill.  For example, if you turn on the \fB\-dx\fR option for
a reminder file with many complex expressions, you'll get a huge amount of
output.  The \fBDEBUG\fR command allows you to control the debugging flags
under program control.  The format is:
.PP
\fBDEBUG\fR [+\fIflagson\fR] [\-\fIflagsoff\fR]
.PP
\fIFlagson\fR and \fIflagsoff\fR consist of strings of the characters "extvl"
which correspond to the debugging options discussed in the command-line
options section.  If preceded with a "+", the corresponding group of
debugging options is switched on.  Otherwise, they are switched off.
For example, you could use this sequence to debug a complicated expression:
.PP
.nf
	DEBUG +x
	set a very_complex_expression(many_args)
	DEBUG \-x
.fi
.PP
.B THE DUMPVARS COMMAND
.PP
The command \fBDUMPVARS\fR displays the values of variables in memory.  Its
format is:
.PP
\fBDUMPVARS\fR [\fIvar\fR...]
.PP
If you supply a space-separated list of variable names, the corresponding
variables are displayed.  If you do not supply a list of variables, then
all variables in memory are displayed.  To dump a system variable,
put its name in the list of variables to dump.  If you put a lone
dollar sign in the list of variables to dump, then all system variables
will be dumped.
.PP
.B THE ERRMSG COMMAND
.PP
The \fBERRMSG\fR command has the following format:
.PP
\fBERRMSG\fR \fIbody\fR
.PP
The \fIbody\fR is passed through the substitution filter (with an
implicit trigger date of \fBtoday()\fR) and printed to the error
output stream.  Example:
.PP
.nf
	IF !defined("critical_var")
		ERRMSG You must supply a value for "critical_var"
		EXIT
	ENDIF
.fi
.PP
.B THE EXIT COMMAND
.PP
The above example also shows the use of the \fBEXIT\fR command.  This
causes an unconditional exit from script processing.  Any queued
timed reminders are discarded.  If you are in calendar mode
(described next), then the calendar processing is aborted.
.PP
If you supply an \fBINT\fR-type expression after the \fBEXIT\fR command,
it is returned to the calling program as the exit status.  Otherwise,
an exit status of 99 is returned.
.PP
.B THE FLUSH COMMAND
.PP
This command simply consists of the word \fBFLUSH\fR on a line by
itself.  The command flushes the standard output and standard error
streams used by \fBRemind\fR.  This is not terribly useful to most
people, but may be useful if you run \fBRemind\fR as a subprocess of
another program, and want to use pipes for communication.
.PP
.SH CALENDAR MODE
.PP
If you supply the \fB\-c\fR, \fB\-s\fR or \fB\-p\fR
command-line option, then \fBRemind\fR
runs in "calendar mode."  In this mode, \fBRemind\fR interprets the script
repeatedly, performing one iteration through the whole file for each day
in the calendar.  Reminders which trigger are saved in internal buffers,
and then inserted into the calendar in the appropriate places.
.PP
If you also supply the \fB\-a\fR option, then \fBRemind\fR will not
include timed reminders in the calendar.
.PP
The \fB\-p\fR option is used in conjunction with the \fBrem2ps\fR
program to produce a calendar in PostScript format.  For example, the
following command will send PostScript code to standard output:
.PP
.nf
	remind -p .reminders | rem2ps
.fi
.PP
You can print a PostScript calendar by piping this to the \fBlpr\fR command.
.PP
If you have a reminder script called ".reminders", and you
execute this command:
.PP
.nf
	remind -c .reminders jan 1993
.fi
.PP
then \fBRemind\fR executes the script 31 times, once for each day in
January.  Each time it executes the script, it increments the value
of \fBtoday()\fR.  Any reminders whose trigger date matches \fBtoday()\fR
are entered into the calendar.
.PP
\fBMSG\fR and \fBCAL\fR-type reminders, by default, have their entire
body inserted into the calendar.  \fBRUN\fR-type reminders are not
normally inserted into the calendar.  However, if you enclose a portion of
the body in the %"...%" sequence, only that portion is inserted.  For
example, consider the following:
.PP
.nf
	REM 6 Jan MSG %"David's birthday%" is %b
.fi
.PP
In the normal mode, \fBRemind\fR would print "David's birthday is today"
on 6 January.  However, in the calendar mode, only the text "David's birthday"
is inserted into the box for 6 January.
.PP
If you explicitly use the %"...%" sequence in a \fBRUN\fR-type reminder,
then the text between the delimiters is inserted into the calendar.
If you use the sequence %"%" in a \fBMSG\fR or \fBCAL\fR-type reminder, then
no calendar entry is produced for that reminder.
.PP
.B PRESERVING VARIABLES
.PP
Because \fBRemind\fR iterates through the script for each day in the calendar,
slow operations may severely reduce the speed of producing a calendar.
.PP
For example, suppose you set the variables "me" and "hostname" as follows:
.PP
.nf
	SET me shell("whoami")
	SET hostname shell("hostname")
.fi
.PP
Normally, \fBRemind\fR clears all variables between iterations in calendar
mode.  However, if certain variables are slow to compute, and will
not change between iterations, you can "preserve" their values with the
\fBPRESERVE\fR command.  Also, since function definitions are preserved
between calendar iterations, there is no need to redefine them on each
iteration.  Thus, you could use the following sequence:
.PP
.nf
	IF ! defined("initialized")
		set initialized 1
		set me shell("whoami")
		set hostname shell("hostname")
		fset func(x) complex_expr
		preserve initialized me hostname
	ENDIF
.fi
.PP
The operation is as follows:  On the first iteration through the script,
"initialized" is not defined.  Thus, the commands between \fBIF\fR and
\fBENDIF\fR are executed.  The \fBPRESERVE\fR command ensures that the
values of initialized, me and hostname are preserved for subsequent
iterations.  On the next iteration, the commands are skipped, since
initialized has remained defined.  Thus, time-consuming operations which
do not depend on the value of \fBtoday()\fR are done only once.
.PP
System variables (those whose names start with '$') are automatically
preserved between calendar iterations.
.PP
Note that for efficiency, \fBRemind\fR caches the reminder script
(and any \fBINCLUDE\fRd files) in memory when producing a calendar.
.PP
Timed reminders are sorted and placed into the calendar in time order.
These are followed by non-timed reminders.  \fBRemind\fR automatically
places the time of timed reminders in the calendar according to the
\fB\-b\fR command-line option.  Reminders in calendar mode are sorted as
if the \fB\-g\fR option had been used; you can change the sort order
in calendar mode by explicitly using the \fB\-g\fR option to specify
a different order from the default.
.PP
.B REPEATED EXECUTION
.PP
If you supply a \fIrepeat\fR parameter on the command line,
and do not use the \fB\-c\fR, \fB\-p\fR, or \fB\-s\fR options, \fBRemind\fR
operates in a similar manner to calendar mode.  It repeatedly executes
the reminder script, incrementing \fBtoday()\fR with each iteration.
The same rules about preserving variables and function definitions
apply.  Note that using \fIrepeat\fR on the command line also enables
the \fB\-q\fR option and disables any \fB\-z\fR option.
As an example, if you want to see how \fBRemind\fR
will behave for the next week, you can type:
.PP
.nf
	remind .reminders '*7'
.fi
.PP
If you want to print the dates of the next 1000 days, use:
.PP
.nf
	(echo 'banner %'; echo 'msg [today()]%') | remind - '*1000'
.fi
.PP
.SH INITIALIZING VARIABLES ON THE COMMAND LINE
.PP
The \fB\-i\fR option is used to initialize variables on the \fBRemind\fR
command line.  The format is \fB\-i\fR\fIvar\fR\fB=\fR\fIexpr\fR, where
\fIexpr\fR is any valid expression.  Note that you may have to use quotes
or escapes to prevent the shell from interpreting special characters in
\fIexpr\fR.  You can have as many \fB\-i\fR options as you want on the
command line, and they are processed in order.  Thus, if a variable is defined
in one \fB\-i\fR option, it can be referred to by subsequent \fB\-i\fR
options.
.PP
Note that if you supply a date on the command line, it is not parsed until
all options have been processed.  Thus, if you use \fBtoday()\fR in any
of the \fB\-i\fR expressions, it will return the same value as
\fBrealtoday()\fR and not the date supplied on the command line.
.PP
Any variables defined on the command line are \fBpreserved\fR as with the
\fBPRESERVE\fR command.
.PP
You should not have any spaces between the \fB\-i\fR option and the equal
sign; otherwise, strange variable names are created which can only be accessed
with the \fBvalue()\fR or \fBdefined()\fR functions.
.PP
If your site uses the \fBRemind-all\fR shell script to mail reminders
to users, the script will initialize the variable \fIremind_all\fR to 1
using the \fB\-i\fR option.  Thus, you can detect when your reminder
script is being processed by \fBRemind-all\fR and can use this information
to control which reminders you want mailed to you.
.PP
.SH MORE ABOUT POSTSCRIPT
.PP
The \fBPS\fR and \fBPSFILE\fR reminders pass PostScript code directly
to the printer.  They differ in that the \fBPS\fR-type reminder passes
its body directly to the PostScript output (after processing by the
substitution filter) while the \fBPSFILE\fR-type's body should
simply consist of a filename.  The \fBRem2ps\fR program will open the
file named in the \fBPSFILE\fR-type reminder, and include its contents in
the PostScript output.
.PP
The PostScript-type reminders for a particular day are included in the
PostScript output in sorted order of priority.  Note that the order
of PostScript commands has a \fImajor\fR impact on the appearance of the
calendars.  For example, PostScript code to shade a calendar box will
obliterate code to draw a moon symbol if the moon symbol code is placed
in the calendar first.  For this reason, you should not provide \fBPS\fR
or \fBPSFILE\fR-type reminders with priorities; instead, you should
ensure that they appear in the reminder script in the correct order.
PostScript code should draw objects working from the background to the
foreground, so that foreground objects properly overlay background ones.
If you prioritize these reminders and run the script using descending
sort order for priorities, the PostScript output will not work.
.PP
All of the PostScript code for a particular date is enclosed
in a \fBsave\fR-\fBrestore\fR pair.  However, if several PostScript-type
reminders are triggered for a single day, each section of PostScript is
not enclosed in a \fBsave\fR-\fBrestore\fR pair - instead, the entire
body of included PostScript is enclosed.
.PP
PostScript-type reminders are executed by the PostScript printer before any
regular calendar entries.  Thus, regular calendar entries will overlay
the PostScript-type reminders, allowing you to create shaded or graphical
backgrounds for particular days.
.PP
Before executing your PostScript code, the origin of the PostScript coordinate
system is positioned to the bottom left-hand corner of the "box" in the
calendar representing \fBtoday()\fR.  This location is exactly in the middle
of the intersection of the bottom and left black lines delineating the box -
you may have to account for the thickness of these lines when calculating
positions.
.PP
Several PostScript variables are available to the PostScript code you supply.
All distance and size variables are in PostScript units (1/72 inch.)  The
variables are:
.TP
LineWidth
The width of the black grid lines making up the calendar.
.TP
Border
The border between the center of the grid lines and the space used to print
calendar entries.  This border is normally blank space.
.TP
BoxWidth and BoxHeight
The width and height of the calendar box, from center-to-center of the
black gridlines.
.TP
InBoxHeight
The height from the center of the bottom black gridline to the top
of the regular calendar entry area.  The space from here to the top
of the box is used only to draw the day number.
.TP
/DayFont, /EntryFont, /SmallFont, /TitleFont and /HeadFont
The fonts used to draw the day numbers, the calendar entries, the small
calendars, the calendar title (month, year)
and the day-of-the-week headings, respectively.
.TP
DaySize, EntrySize, TitleSize and HeadSize
The sizes of the above fonts.  (The size of the small calendar font
is \fInot\fR defined here.)  For example, if you wanted to print
the Hebrew date next to the regular day number in the calendar, use:
.PP
.nf
	REM PS Border BoxHeight Border sub DaySize sub moveto \\
	   /DayFont findfont DaySize scalefont setfont \\
	   ([hebday(today())] [hebmon(today())]) show
.fi
.PP
.RS
Note how /DayFont and DaySize are used.
.RE
.PP
Note that if you supply PostScript code, it is possible to produce invalid
PostScript files.  Always test your PostScript thoroughly with a PostScript
viewer before sending it to the printer.  You should not use any document
structuring comments in your PostScript code.
.PP
.SH DAEMON MODE
.PP
If you use the \fB\-z\fR command-line option, \fBRemind\fR runs in the
"daemon" mode.  In this mode, no "normal" reminders are issued.
Instead, only timed reminders are collected and queued, and are then
issued whenever they reach their trigger time.
.PP
In addition, \fBRemind\fR wakes up every few minutes to check the modification
date on the reminder script (the filename supplied on the command line.)
If \fBRemind\fR detects that the script has changed, it re-executes itself
in daemon mode, and interprets the changed script.
.PP
In daemon mode, \fBRemind\fR also re-reads the remind script when it
detects that the system date has changed.
.PP
In daemon mode, \fBRemind\fR acts as if the \fB\-f\fR option had been used,
so to run in the daemon mode in the background, use:
.PP
.nf
	remind -z .reminders &
.fi
.PP
If you use \fBsh\fR or \fBbash\fR, you may have to use the "nohup" command
to ensure that the daemon is not killed when you log out.
.PP
.SH SORTING REMINDERS
.PP
The \fB\-g\fR option causes \fBRemind\fR to sort reminders by
trigger date, time and priority before issuing them.  Note that reminders are
still calculated in the order encountered in the script.  However, rather
than being issued immediately, they are saved in an internal buffer.
When \fBRemind\fR has finished processing the script, it issues the
saved reminders in sorted order.  The \fB\-g\fR option can be followed
by up to three characters, which must be "a" or "d".  The first character
specifies the sort order by trigger date (ascending or descending),
the second specifies the sort order by trigger time and the third
specifies the sort order by priority.  The default is
to sort all fields in ascending order.
.PP
In ascending order, reminders are issued with the most imminent first.
Descending order is the reverse.  Reminders are always sorted by
trigger date, and reminders with the same trigger date are then sorted
by trigger time.  Non-timed reminders are always issued after timed
reminders in this mode.  If two reminders have the same date and time,
then the priority is used to break ties.  Reminders with the same date,
time and priority are issued in the order they were encountered.
.PP
You can define a user-defined function called SORTBANNER which takes one
\fBDATE\fR-type argument.  In sort mode, the following sequence happens:
.PP
If \fBRemind\fR notices that the next reminder to issue has a different
trigger date from the previous one (or if it is the first one to be
issued), then SORTBANNER is called with the trigger date as its argument.
The result is coerced to a string, and passed through the substitution
filter with the appropriate trigger date.  The result is then displayed.
.PP
Here's an example - consider the following fragment:
.PP
.nf
	# Switch off the normal banner
	BANNER %
	REM 11 March 1993 ++1 MSG Not so important
	REM 17 March 1993 ++7 MSG Way in the future
	REM 10 March 1993 MSG Important Reminder
	REM 11 March 1993 ++1 MSG Not so important - B
	FSET sortbanner(x) iif(x == today(), \\
		"***** THINGS TO DO TODAY *****", \\
		"----- Things to do %b -----")
.fi
.PP
Running this with the \fB-gaa\fR option on 10 March 1993
produces the following output:
.PP
.nf
	***** THINGS TO DO TODAY *****

	Important Reminder

	----- Things to do tomorrow -----

	Not so important

	Not so important - B

	----- Things to do in 7 days' time -----

	Way in the future
.fi
.PP
You can use the \fBargs()\fR built-in function to determine whether or
not SORTBANNER has been defined.  (This could be used, for example, to
provide a default definition for SORTBANNER in a system-wide file included
at the end of the user's file.)  Here's an example:
.PP
.nf
	# Create a default sortbanner function if it hasn't already
	# been defined
	if args("sortbanner") != 1
		fset sortbanner(x) "--- Things to do %b ---"
	endif
.fi
.PP
.SH MSGPREFIX() AND MSGSUFFIX()
.PP
You can define two functions in your script called \fBmsgprefix()\fR
and \fBmsgsuffix()\fR.  They should each accept one argument, a number
from 0 to 9999.
.PP
In normal mode, for \fBMSG\fR- and \fBMSF\fR-type reminders,
the following sequence occurs when
\fBRemind\fR triggers a reminder:
.TP
o
If \fBmsgprefix()\fR is defined, it is evaluated with the priority
of the reminder as its argument.  The result is printed.  It is
\fInot\fR passed through the substitution filter.
.TP
o
The body of the reminder is printed.
.TP
o
If \fBmsgsuffix()\fR is defined, it is evaluated with the priority
of the reminder as its argument.  The result is printed.  It is
\fInot\fR passed through the substitution filter.
.PP
Here's an example:  The following definition causes priority-0
reminders to be preceded by "URGENT", and priority-6000 reminders to
be preceded by "(not important)".
.PP
.nf
	fset msgprefix(x) iif(x==0, "URGENT: ", \\
	     x==6000, "(not important) ", "")
.fi
.PP
In Calendar Mode (with the \fB\-c\fR, \fB\-s\fR or \fB\-p\fR options),
an analagous pair of functions named \fBcalprefix()\fR and
\fBcalsuffix()\fR can be defined.  They work with all reminders which
produce an entry in the calendar (i.e., \fBCAL\fR- and possibly
\fBRUN\fR-type reminders as well as \fBMSG\fR-type reminders.)
.PP
.B NOTES
.PP
Normally, the body of a reminder is followed by a carriage return.
Thus, the results of \fBmsgsuffix()\fR will appear on the next
line.  If you don't want this, end the body of the reminder with a
percentage sign, "%".  If you want a space between your reminders,
simply include a carriage return (\fBchar(13)\fR) as part of the
\fBmsgsuffix()\fR return value.
.PP
If \fBRemind\fR has problems evaluating \fBmsgprefix()\fR,
\fBmsgsuffix()\fR or \fBsortbanner()\fR, you will see a lot of
error messages.  For an example of this, define the following:
.PP
.nf
	fset msgprefix(x) x/0
.fi
.PP
.SH FOREIGN LANGUAGE SUPPORT
.PP
Your version of \fBRemind\fR may have been compiled to support a
language other than English.  This support may or may not be complete -
for example, all error and usage messages may still be in English.
However, at a minimum, foreign-language versions of \fBRemind\fR will
output names of months and weekdays in the foreign language.  Also,
the substitution mechanism will substitute constructs suitable for the
foreign language rather than for English.
.PP
A foreign-language version of \fBRemind\fR will accept either the English
or foreign-language names of weekdays and months in a reminder script.
However, for compatibility between versions of \fBRemind\fR, you should
use only the English names in your scripts.  Also, if your C compiler or
run-time libraries are not "8-bit clean" or don't understand the ISO-Latin
character set, month or day names with accented letters may not be
recognized.
.PP
.SH THE HEBREW CALENDAR
.PP
\fBRemind\fR has support for the Hebrew calendar, which is a luni-solar
calendar.  This allows you to create reminders for Jewish holidays,
jahrzeits (anniversaries of deaths) and smachot (joyous occasions.)
.PP
.B THE HEBREW YEAR
.PP
The Hebrew year has 12 months, alternately 30 and 29 days long.  The months
are: Tishrey, Heshvan, Kislev, Tevet, Shvat, Adar, Nisan, Iyar, Sivan, Tamuz,
Av and Elul.  In Biblical times, the year started in Nisan, but Rosh Hashana
(Jewish New Year) is now celebrated on the 1st and 2nd of Tishrey.
.PP
In a cycle of 19 years, there are 7 leap years, being years 3, 6, 8, 11,
14, 17 and 19 of the cycle.  In a leap year, an extra month of 30 days
is added before Adar.  The two Adars are called Adar A and Adar B.
.PP
For certain religious reasons, the year cannot start on a Sunday, Wednesday
or Friday.  To adjust for this, a day is taken off Kislev or added to Heshvan.
Thus, a regular year can have from 353 to 355 days, and a leap year from
383 to 385.
.PP
When Kislev or Heshvan is short, it is called \fIchaser\fR, or lacking.  When
it is long, it is called \fIshalem\fR, or full.
.PP
The Jewish date changes at sunset.  However, \fBRemind\fR will change the date
at midnight, not sunset.  So in the period between sunset and midnight,
Remind will be a day earlier than the true Jewish date.  This should not be
much of a problem in practice.
.PP
The computations for the Jewish calendar were based on the program "hdate"
written by Amos Shapir of the Hebrew University of Jerusalem, Israel.  He
also supplied the preceding explanation of the calendar.
.PP
.B HEBREW DATE FUNCTIONS
.TP
.B hebday(d_date)
Returns the day of the Hebrew month corresponding to the \fIdate\fR
parameter.  For example, 12 April 1993 corresponds to 21 Nisan 5753.
Thus, hebday('1993/04/12') returns 21.
.TP
.B hebmon(d_date)
Returns the name of the Hebrew month corresponding to \fIdate\fR.
For example, hebmon('1993/04/12') returns "Nisan".
.TP
.B hebyear(d_date)
Returns the Hebrew year corresponding to \fIdate\fR.  For example,
hebyear('1993/04/12') returns 5753.
.TP
.B hebdate(i_day, s_hebmon [,id_yrstart [,i_jahr [,i_aflag]]])
The \fBhebdate()\fR function is the most complex of the Hebrew support
functions.  It can take from 2 to 5 arguments.  It returns a \fBDATE\fR
corresponding to the Hebrew date.
.PP
.RS
The \fIday\fR parameter can range from 1 to 30, and specifies the day of
the Hebrew month.  The \fIhebmon\fR parameter is a string which must name
one of the Hebrew months specified above.  Note that the month must be spelled
out in full, and use the English transliteration shown previously.  You can
also specify "Adar A" and "Adar B."  Month names are not case-sensitive.
.PP
The \fIyrstart\fR parameter can either be a \fBDATE\fR or an \fBINT\fR.  If
it is a \fBDATE\fR, then the \fBhebdate()\fR scans for the first Hebrew
date on or after that date.  For example:
.PP
.nf
		hebdate(15, "Nisan", '1990/01/01')
.fi
.PP
returns 1990/03/30, because that is the first occurrence of 15 Nisan on
or after 1 January 1990.
.PP
If \fIyrstart\fR is an \fBINT\fR, it is interpreted as a Hebrew year.  Thus:
.PP
.nf
		hebdate(22, "Kislev", 5756)
.fi
.PP
returns 1995/12/15, because that date corresponds to 22 Kislev, 5756.  Note
that none of the Hebrew date functions will work with dates outside
\fBRemind's\fR normal range for dates.
.PP
If \fIyrstart\fR is not supplied, it defaults to \fBtoday()\fR.
.PP
The \fIjahr\fR modifies the behaviour of \fBhebdate()\fR as follows:
.PP
If \fIjahr\fR is 0 (the default),
then \fBhebdate()\fR keeps scanning until it
finds a date which exactly satisfies the other parameters.  For example:
.PP
.nf
		hebdate(30, "Adar A", 1993/01/01)
.fi
.PP
returns 1995/03/02, corresponding to 30 Adar A, 5755, because that is the
next occurrence of 30 Adar A after 1 January, 1993.  This behaviour is
appropriate for Purim Katan, which only appears in leap years.
.PP
If \fIjahr\fR is 1, then the date is modified as follows:
.TP
o
30 Heshvan is converted to 1 Kislev in years when Heshvan is \fIchaser\fR
.TP
o
30 Kislev is converted to 1 Tevet in years when Kislev is \fIchaser\fR
.TP
o
30 Adar A is converted to 1 Nisan in non-leapyears
.TP
o
Other dates in Adar A are moved to the corresponding day in Adar in
non-leapyears
.PP
This behaviour is appropriate for smachot (joyous occasions) and for
some jahrzeits - see "JAHRZEITS."
.PP
if \fIjahr\fR is 2, then the date is modified as follows:
.TP
o
30 Kislev and 30 Heshvan are converted to 29 Kislev and 29 Heshvan,
respectively, if the month is \fIchaser\fR
.TP
o
30 Adar A is converted to 30 Shvat in non-leapyears
.TP
o
Other dates in Adar A are moved to the corresponding day in Adar in
non-leapyears
.PP
if \fIjahr\fR is not 0, 1, or 2, it is interpreted as a Hebrew year,
and the behaviour is calculated as described in the next section,
"JAHRZEITS."
.PP
The \fIaflag\fR parameter modifies the behaviour of the function for
dates in Adar during leap years.  The \fIaflag\fR is \fIonly\fR used
if \fIyrstart\fR is a \fBDATE\fR type.
.PP
The \fIaflag\fR only affects date calculations if \fIhebmon\fR is
specified as "Adar".  In leap years, the following algorithm is followed:
.TP
o
If \fIaflag\fR is 0, then the date is triggered in Adar B.  This is
the default.
.TP
o
If \fIaflag\fR is 1, then the date is triggered in Adar A.  This may
be appropriate for jahrzeits in the Ashkenazi tradition; consult a
rabbi.
.TP
o
If \fIaflag\fR is 2, then the date is triggered in both Adar A and Adar
B of a leap year.  Some Ashkenazim perform jahrzeit in both Adar A and
Adar B.
.RE
.PP
.B JAHRZEITS
.PP
A jahrzeit is a yearly commemoration of someone's death.  It normally takes
place on the anniversary of the death, but may be delayed if burial is
delayed - consult a rabbi for more information.
.PP
In addition, because some months change length, it is not obvious which day
the anniversary of a death is.  The following rules are used:
.TP
o
If the death occurred on 30 Heshvan, and Heshvan in the year after the
death is \fIchaser\fR, then the jahrzeit is observed on 29 Heshvan in years
when Heshvan is \fIchaser\fR.  Otherwise, the yahrzeit is observed on 1
Kislev when Heshvan is \fIchaser\fR.
.TP
o
If the death occurred on 30 Kislev, and Kislev in the year after the
death is \fIchaser\fR, then the jahrzeit is observed on 29 Kislev in years
when Kislev is \fIchaser\fR.  Otherwise, the yahrzeit is observed on 1
Tevet when Kislev is \fIchaser\fR.
.TP
o
If the death occurred on 1-29 Adar A, it is observed on 1-29 Adar in
non-leapyears.
.TP
o
If the death occurred on 30 Adar A, it is observed on 30 Shvat in a
non-leapyear.
.PP
Specifying a Hebrew year for the \fIjahr\fR parameter causes the
correct behaviour to be selected for a death in that year.  You may
also have to specify \fIaflag\fR, depending on your tradition.
.PP
The jahrzeit information was supplied by Frank Yellin, who quoted
"The Comprehensive Hebrew Calendar" by Arthur Spier, and "Calendrical
Calculations" by E. M. Reingold and Nachum Dershowitz.
.PP
.SH MISCELLANEOUS
.PP
.B COMMAND ABBREVIATIONS
.PP
The following tokens can be abbreviated:
.TP
o
\fBREM\fR can be omitted - it is implied if no other valid command
is present.
.TP
o
\fBCLEAR-OMIT-CONTEXT\fR --> \fBCLEAR\fR
.TP
o
\fBPUSH-OMIT-CONTEXT\fR --> \fBPUSH\fR
.TP
o
\fBPOP-OMIT-CONTEXT\fR --> \fBPOP\fR
.TP
o
\fBDUMPVARS\fR --> \fBDUMP\fR
.TP
o
\fBBANNER\fR --> \fBBAN\fR
.TP
o
\fBINCLUDE\fR --> \fBINC\fR
.TP
o
\fBSCANFROM\fR --> \fBSCAN\fR
.PP
.B NIFTY EXAMPLES
.PP
This section is a sampling of what you can do with \fBRemind\fR.
.PP
.nf
	REM 5 Feb 1991 AT 14:00 +45 *30 \\
	RUN mail -s "Meeting at %2" $LOGNAME </dev/null &
.fi
.PP
On 5 February, 1991, this reminder will mail
you reminders of a 2:00pm meeting at 1:15,
1:45 and 2:00.  The subject of the mail message will be "Meeting at 2:00pm"
and the body of the message will be blank.
.PP
.nf
	REM AT 17:00 RUN echo "5:00pm - GO HOME!" | xless -g +0+0 &
.fi
.PP
This reminder will pop up an xless window at 5:00pm every day.  The xless
window will contain the line "5:00pm - GO HOME!"
.PP
.nf
	REM AT 23:59 RUN (sleep 120; remind -a [filename()]) &
.fi
.PP
This reminder will run at one minute to midnight.  It will cause a new
\fBRemind\fR process to start at one minute past midnight.  This allows you to
have a continuous reminder service so you can work through the night and
still get timed reminders for early in the morning.  Note that this
trick is no longer necessary, providing you run \fBRemind\fR in
daemon mode.
.PP
.nf
	remind \-c12 /dev/null Jan 1993
.fi
.PP
This invocation of \fBRemind\fR will cause it to print a calendar for
1993, with all entries left blank.
.PP
.nf
	REM CAL [trigdate()-date(year(trigdate()), 1, 1)+1]
.fi
.PP
This example puts an entry in each box of a calendar showing the number
(1-365 or 366) of the day of the year.
.PP
.nf
	REM Tue 2 Nov SATISFY (year(trigdate())%4) == 0
	IF trigvalid()
		REM [trigger(trigdate())] ++5 MSG \\
		U.S. Presidential Election!!
	ENDIF
.fi
.PP
This example warns you 5 days ahead of each American presidential
election.  The first \fBREM\fR command calculates the first Tuesday after
the first Monday in November.  (This is equivalent to the first
Tuesday on or after 2 November.)  The \fBSATISFY\fR clause ensures
that the trigger date is issued only in election years, which are
multiples of 4.  The second \fBREM\fR command actually issues the
reminder.
.PP
.B DETAILS ABOUT TRIGGER COMPUTATION
.PP
Here is a \fIconceptual\fR description of how triggers are calculated.
Note that \fBRemind\fR actually uses a much more efficient procedure,
but the results are the same as if the conceptual procedure had been
followed.
.PP
\fBRemind\fR starts from the current date (that is, the value of
\fBtoday()\fR) and scans forward, examining each day one at a time
until it finds a date which satisfies the trigger, or can prove that
no such dates (on or later than \fBtoday()\fR) exist.
.PP
If \fBRemind\fR is executing a \fBSATISFY\fR-type reminder, it evaluates
the expression with \fBtrigdate()\fR set to the date found above.  If
the expression evaluates to zero or the null string, \fBRemind\fR continues
the scanning procedure described above, starting with the day after the
trigger found above.
.PP
The \fBSCANFROM\fR clause (having a syntax similar to \fBUNTIL\fR)
can modify the search strategy used.  In this case, \fBRemind\fR begins the
scanning procedure at \fIscan_date\fR, which is the date specified in
the \fBSCANFROM\fR clause.  For example:
.PP
.nf
	REM Mon 1 SCANFROM 17 Jan 1992 MSG Foo
.fi
.PP
The example above will always have a trigger date of Monday, 3 February 1992.
That is because \fBRemind\fR starts scanning from 17 January 1992, and
stops scanning as soon as it hits a date which satisfies "Mon 1."
.PP
The main use of \fBSCANFROM\fR is in situations where you want to
calculate the positions of floating holidays.  Consider the Labour
Day example shown much earlier.  Labour Day is the first Monday
in September.  It can move over a range of 7 days.  Consider the
following sequence:
.PP
.nf
	REM Mon 1 Sept SCANFROM [trigger(today()-7)] SATISFY 1
	OMIT [trigger(trigdate())]

	REM Mon AFTER MSG Hello
.fi
.PP
The \fBSCANFROM\fR clause makes sure that \fBRemind\fR begins scanning
from 7 days before the current date.  This ensures that Labour Day for
the current year will continue to be triggered until 7 days after it has
occurred.  This allows you to safely use the AFTER keyword as shown.
.PP
In general, use \fBSCANFROM\fR as shown for safe movable \fBOMITs\fR.  The
amount you should scan back by (7 days in the example above) depends on
the number of possible consecutive \fBOMITted\fR days which may occur, and
on the range of the movable holiday.  Generally, a value of 7 is safe.
.PP
Note that if you use one \fBREM\fR command to calculate a trigger date,
perform date calculations (addition or subtraction, for example) and
then use the modified date in a subsequent \fBREM\fR command, the results
\fImay not be what you intended.\fR  This is because you have circumvented
the normal scanning mechanism.  You should try to write \fBREM\fR commands
which compute trigger dates that can be used unmodified in subsequent
\fBREM\fR commands.  The file "defs.rem" which comes with the \fBRemind\fR
distribution contains examples.
.PP
.B DETAILS ABOUT TRIGVALID()
.PP
The \fBtrigvalid()\fR function returns 1 if \fBRemind\fR could find a trigger
date for the previous \fBREM\fR or \fBIFTRIG\fR command.  More specifically,
it returns 1 if \fBRemind\fR finds a date \fInot before the starting
date of the scanning\fR which
satisfies the trigger.  In addition, there is one special case in which
\fBtrigvalid()\fR returns 1 and \fBtrigdate()\fR returns a meaningful result:
.PP
If the \fBREM\fR or \fBIFTRIG\fR command did not contain an \fBUNTIL\fR
clause, and contained all of the \fIday\fR, \fImonth\fR and \fIyear\fR
components, then \fBRemind\fR will correctly compute a trigger date, even
if it happens to be before the start of scanning.
Note that this behaviour is not true for
versions of \fBRemind\fR prior to 03.00.01.
.SH AUTHOR
.PP
David F. Skoll wrote \fBRemind\fR.  The moon code was copied largely
unmodified from "moontool" by John Walker.  The sunrise and sunset
functions use ideas from programs by Michael Schwartz and Marc
T. Kaufman.  The Hebrew calendar support was taken from "hdate" by
Amos Shapir.  OS/2 support was done by Darrel Hankerson, Russ Herman,
and Norman Walsh.  The supported foreign languages and their
translators are listed below.  Languages marked "complete" support
error messages and usage instructions in that language; all others
only support the substitution filter mechanism and month/day names.
.PP
\fBGerman\fR --
Wolfgang Thronicke
.PP
\fBDutch\fR --
Willem Kasdorp and Erik-Jan Vens
.PP
\fBFinnish\fR --
Mikko Silvonen (complete)
.PP
\fBFrench\fR --
Laurent Duperval (complete)
.PP
\fBNorwegian\fR --
Trygve Randen
.PP
\fBDanish\fR --
Mogens Lynnerup
.PP
\fBPolish\fR --
Jerzy Sobczyk (complete)
.PP
\fBBrazilian Portuguese\fR --
Marco Paganini (complete)
.PP
\fBItalian\fR --
Valerio Aimale
.PP
\fBRomanian\fR --
Liviu Daia
.SH BUGS
.PP
There's no good reason why read-only system variables are not
implemented as functions, or why functions like \fBversion()\fR, etc.
are not implemented as read-only system variables.
.PP
Hebrew dates in \fBRemind\fR change at midnight instead of sunset.
.PP
Language should be selectable at run-time, not compile-time.  Don't
expect this to happen soon!
.PP
The UTC functions may not be reliable under MS-DOS.
.PP
The MS-DOS version of \fBRemind\fR does not support queuing or timed
activation of reminders.
.PP
\fBRemind\fR has some built-in limits on total line length,
substitution buffer length, number of global \fBOMIT\fRs, etc.
.PP
.SH BIBLIOGRAPHY
.PP
Nachum Dershowitz and Edward M. Reingold, "Calendrical Calculations",
\fISoftware\-Practice and Experience\fR, Vol. 20(9), Sept. 1990,
pp 899-928.
.PP
L. E. Doggett, \fIAlmanac for computers for the year 1978\fR, Nautical
Almanac Office, USNO.
.PP
Richard Siegel and Michael and Sharon Strassfeld, \fIThe First Jewish
Catalog\fR, Jewish Publication Society of America.
.PP
.SH SEE ALSO
.PP
rem, elm, kall, rem2ps, tkremind