Reorder man page; add explanation of how omit interacts with time zone.

This commit is contained in:
Dianne Skoll
2025-09-06 11:08:34 -04:00
parent f8781276e2
commit 7064893ff2

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@@ -2043,56 +2043,6 @@ In Purge Mode, \fBRemind\fR will not purge TODOs unless they have been marked
as complete. In the case of a recurring TODO, \fBRemind\fR will not purge
it until the last occurrence is marked as complete.
.PP
.SH TIMEZONE SUPPORT
.PP
The \fBREM\fR command supports an optional \fBTZ\fR keyword, which should
be followed by the \fIcase-sensitive\fR time zone name in which the
command is to be interpreted. Note that if you use the \fBTZ\fR keyword,
then you \fImust also\fR use an \fBAT\fR clause. Here are some examples:
.PP
.nf
REM Wednesday AT 14:00 TZ America/Toronto MSG 2PM Eastern (%2).
REM Wednesday AT 23:59 TZ America/Los_Angeles SATISFY [$Td == 13] MSG Foo %b %2.
.fi
.PP
Within a \fBSATISFY\fR clause and an \fBOMITFUNC\fR function, all
trigger functions and the trigger date are interpreted \fIin the time
zone specified in the \fBREM\fI command\fR. Outside the \fBREM\fR
command, however, trigger functions are adjusted to the local time
zone. If the local time zone is UTC and we feed \fBRemind\fR the
following file on 2025-09-04 UTC:
.PP
.nf
SET $AddBlankLines 0
BANNER %
REM Wednesday AT 14:00 TZ America/Toronto MSG 2PM Eastern (%2).
set a $T
set b $Tt
REM MSG a = [a], b = [b]
REM Wednesday AT 23:59 TZ America/Los_Angeles SATISFY [$Td == 13] MSG Foo %b %2.
set c $T
set d $Tt
REM MSG c = [c], d = [d]
.fi
.PP
Then the output is as follows:
.PP
.nf
a = 2025-09-10, b = 18:00
c = 2026-05-14, d = 06:59
.fi
.PP
That is because the trigger date of the first (Wednesday, 2025-09-10
at 14:00 Eastern time) is 2025-09-10 at 18:00 UTC. In the second case,
Wednesday, 13 May 2026 is the SATISFied trigger date, which is
adjusted to Thursday, 14 May 2026 at 06:59 UTC because of the
time zone adjustment.
.PP
If you use an invalid time zone name after the \fBTZ\fR keyword,
results are undefined. Unfortunately, \fBRemind\fR cannot diagnose
this error becase the C library \fBtzset()\fR function has no
error return.
.PP
.SH THE OMIT COMMAND
.PP
In addition to being a keyword in the \fBREM\fR command,
@@ -2257,6 +2207,81 @@ the first day of the month. The local \fBOMIT\fR keyword causes the
Finally, the \fBAFTER\fR keyword will keep moving the reminder forward
until it has passed any holidays specified with global \fBOMIT\fR
commands.
.PP
.SH TIMEZONE SUPPORT
.PP
The \fBREM\fR command supports an optional \fBTZ\fR keyword, which should
be followed by the \fIcase-sensitive\fR time zone name in which the
command is to be interpreted. Note that if you use the \fBTZ\fR keyword,
then you \fImust also\fR use an \fBAT\fR clause. Here are some examples:
.PP
.nf
REM Wednesday AT 14:00 TZ America/Toronto MSG 2PM Eastern (%2).
REM Wednesday AT 23:59 TZ America/Los_Angeles SATISFY [$Td == 13] MSG Foo %b %2.
.fi
.PP
Within a \fBSATISFY\fR clause and an \fBOMITFUNC\fR function, all
trigger functions and the trigger date are interpreted \fIin the time
zone specified in the \fBREM\fI command\fR. Outside the \fBREM\fR
command, however, trigger functions are adjusted to the local time
zone. If the local time zone is UTC and we feed \fBRemind\fR the
following file on 2025-09-04 UTC:
.PP
.nf
SET $AddBlankLines 0
BANNER %
REM Wednesday AT 14:00 TZ America/Toronto MSG 2PM Eastern (%2).
set a $T
set b $Tt
REM MSG a = [a], b = [b]
REM Wednesday AT 23:59 TZ America/Los_Angeles SATISFY [$Td == 13] MSG Foo %b %2.
set c $T
set d $Tt
REM MSG c = [c], d = [d]
.fi
.PP
Then the output is as follows:
.PP
.nf
a = 2025-09-10, b = 18:00
c = 2026-05-14, d = 06:59
.fi
.PP
That is because the trigger date of the first (Wednesday, 2025-09-10
at 14:00 Eastern time) is 2025-09-10 at 18:00 UTC. In the second case,
Wednesday, 13 May 2026 is the SATISFied trigger date, which is
adjusted to Thursday, 14 May 2026 at 06:59 UTC because of the
time zone adjustment.
.PP
If you use an invalid time zone name after the \fBTZ\fR keyword,
results are undefined. Unfortunately, \fBRemind\fR cannot diagnose
this error becase the C library \fBtzset()\fR function has no
error return.
.PP
In a reminder with the \fBTZ\fR keyword, OMIT dates are evaluated in
the specified time zone. Here's an example: Suppose the local time zone
is America/Toronto and you have this script:
.PP
.nf
# A Friday
OMIT 2025-09-05
# A Saturday
OMIT 2025-09-13
REM Saturday AT 01:00 TZ Europe/Amsterdam SKIP MSG Early Sat AM
.fi
.PP
On 2025-09-05 in the America/Toronto time zone, the reminder \fIwill\fR
trigger. Even though 2025-09-05 has been OMITted, the SKIP keyword
evaluates the date in the Europe/Amsterdam time zone, and 2025-09-06
(the trigger date) is \fInot\fR omitted.
.PP
Conversely, on 2025-09-12 in the America/Toronto time zone, the
reminder will \fInot\fR trigger. Even though 2025-09-12 is not OMITted,
2025-09-13 is, and that is the trigger date in the Europe/Amsterdam
time zone.
.PP
.SH THE DO, INCLUDE AND SYSINCLUDE COMMANDS
.PP
\fBRemind\fR allows you to include other files in your reminder script,