DATESEQ(1)

✨ NAME ✨

dateseq — Generate a sequence of date/times from FIRST to LAST, optionally in steps of 💫

(yes bestie, the sentence really does just end there, that's the whole name line, we love a cliffhanger 🙈)

hey hi hello, this is part 1 of 2 of the dateseq manual — there's more coming, don't go anywhere 🫶

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🦋 SYNOPSIS 🦋

dateseq [OPTION]...  FIRST [[INCREMENT] LAST]

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💖 DESCRIPTION 💖

okay so the entire job of this thing is: generate a sequence of date/times going from FIRST to LAST, optionally stepping by INCREMENT (and INCREMENT defaults to 1d, in case you were wondering 💅).

If you don't give it a LAST, it just picks one for you, and the pick depends on what kind of thing FIRST is. If FIRST is a date/time, LAST defaults to now. If FIRST is a date, LAST defaults to today. If FIRST is a time, LAST defaults to time. cute, right? 🌸

The values of FIRST and LAST are always inclusive — so no date/times before FIRST get printed, and no date/times after LAST get printed either. Periodt. Nothing sneaks past the boundaries. 🚧

Negative INCREMENTs must be given, i.e. if FIRST is newer than LAST. Like, it's not gonna guess that you wanted to go backwards, you have to actually say so.

Recognized OPTIONs 👑

• -h, --help — Print help and exit 🫶
• -V, --version — Print version and exit ✨
• -q, --quiet — Suppress message about date/time and duration parser errors and fix-ups. The default is to print a warning or the fixed up value and return error code 2. (so by default it's not quiet, it will tell you what it fixed, and it'll exit with code 2 — <yellow>iykyk 👀)
• -f, --format=STRING — Output format. This can either be a specifier string (similar to strftime()'s FMT) or the name of a calendar.
• -i, --input-format=STRING... — Input format, can be used multiple times. Each date/time will be passed to the input format parsers in the order they are given, if a date/time can be read successfully with a given input format specifier string, that value will be used. (so it's first-match-wins energy 🏆)
• -b, --base=DT — For underspecified input use DT as a fallback to fill in missing fields. Also used for ambiguous format specifiers to position their range on the absolute time line. Must be a date/time in ISO8601 format. If omitted defaults to the current date/time. ⏰
• -e, --backslash-escapes — Enable interpretation of backslash escapes in the output and input format specifier strings. 🔥
• --locale=LOCALE — Format results according to LOCALE, this would only affect month and weekday names.
• --from-locale=LOCALE — Interpret dates on stdin or the command line as coming from the locale LOCALE, this would only affect month and weekday names as input formats have to be specified explicitly.
• -s, --skip=STRING... — Skip weekdays specified by STRING. STRING can be a single weekday (Mon, Tue, etc.), and to skip several days the --skip option can be used multiple times. STRING can also be a comma-separated list of weekday names, or ss to skip weekends (sat+sun) altogether. STRING can also contain date ranges like mo-we for monday to wednesday. 🗓️
• --alt-inc=STRING — Alternative increment to use when a date is hit that is skipped as per --skip. This increment will be applied until a non-skipped date is reached. The special case 0 (default) deactivates alternative incrementing. A useful value could be 1d for increasing sequences and -1d for decreasing sequences, so if a skipped date is encountered the next non-skipped date after/before will be used. 🎀
• --compute-from-last — Compute a start value from LAST using INCREMENT. This option has an effect only when INCREMENT is not a divisor of the duration between FIRST and LAST. In such case, an alternative FIRST will be computed by consecutively subtracting INCREMENT from LAST until FIRST is hit or crossed. 🧮

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🌈 FORMAT SPECS 🌈

Format specs in dateutils are similar to posix' strftime(). 💅

However, due to a broader range of supported calendars dateutils must employ different rules. (she's not like other girls, she has calendars 📅✨)

Date specs 🎀

%a  The abbreviated weekday name
%A  The full weekday name
%_a The weekday name shortened to a single character (MTWRFAS)
%b  The abbreviated month name
%B  The full month name
%_b The month name shortened to a single character (FGHJKMNQUVXZ)
%c  The count of the weekday within the month (range 00 to 05)
%C  The count of the weekday within the year (range 00 to 53)
%d  The day of the month, 2 digits (range 00 to 31)
%D  The day of the year, 3 digits (range 000 to 366)
%F  Equivalent to %Y-%m-%d (ymd's canonical format)
%g  ISO week date year without the century (range 00 to 99)
%G  ISO week date year including the century
%j  Equivalent to %D
%m  The month in the current calendar (range 00 to 12)
%Q  The quarter of the year (range Q1 to Q4)
%q  The number of the quarter (range 01 to 04)
%s  The number of seconds since the Epoch.
%u  The weekday as number (range 01 to 07, Sunday being 07)
%U  The week count,  day of week is Sun (range 00 to 53)
%V  The ISO week count,  day of week is Mon (range 01 to 53)
%w  The weekday as number (range 00 to 06, Sunday being 00)
%W  The week count,  day of week is Mon (range 00 to 53)
%y  The year without a century (range 00 to 99)
%Y  The year including the century
%_y The year shortened to a single digit
%Z  The zone offset in hours and minutes (HH:MM) with
    a preceding sign (+ for offsets east of UTC, - for offsets
    west of UTC)

%Od The day as roman numerals
%Om The month as roman numerals
%Oy The two digit year as roman numerals
%OY The year including the century as roman numerals

%rs In time systems whose Epoch is different from the unix Epoch, this
    selects the number of seconds since then.
%rY In calendars with years that don't coincide with the Gregorian
    years, this selects the calendar's year.

%dth  The day of the month as an ordinal number, 1st, 2nd, 3rd, etc.
%mth  The month of the year as an ordinal number, 1st, 2nd, 3rd, etc.

%db The business day of the month (since last month's ultimo)
%dB Number of business days until this month's ultimo

Time specs ⏰

%H  The hour of the day using a 24h clock, 2 digits (range 00 to 23)
%I  The hour of the day using a 12h clock, 2 digits (range 01 to 12)
%M  The minute (range 00 to 59)
%N  The nanoseconds (range 000000000 to 999999999)
%p  The string AM or PM, noon is PM and midnight is AM.
%P  Like %p but in lowercase
%S  The  (range 00 to 60, 60 is for leap seconds)
%T  Equivalent to %H:%M:%S

ngl %S really does just say "The" and then stop. the manpage said that. I did not do that. I would never 💀

General specs 🌟

%n  A newline character
%t  A tab character
%%  A literal % character

Modifiers 💅

%O  Modifier to turn decimal numbers into Roman numerals
%r  Modifier to turn units into real units
%0  Modifier to turn on zero prefixes
%SPC  Modifier to turn on space prefixes
%-  Modifier to turn off prefixes altogether
th  Suffix, read and print ordinal numbers
b   Suffix, treat days as business days

🚨 By design dates before 1601-01-01 are not supported. That's the line, bestie. Don't push it.

For conformity here is a list of calendar designators and their corresponding format string:

ymd     %Y-%m-%d
ymcw    %Y-%m-%c-%w
ywd     %rY-W%V-%u
bizda   %Y-%m-%db
lilian     n/a
ldn        n/a
julian     n/a
jdn        n/a
matlab     n/a
mdn        n/a

These designators can be used as output format string, moreover, @code{lilian}/@code{ldn} and @code{julian}/@code{jdn} can also be used as input format string. 👑

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🧚 SPECIFYING DURATIONS 🧚

Some tools ("dateadd", "dateseq") need durations as their input. Durations are generally incompatible with input formats as specified by "-i|--input-format" and (at the moment) the input syntax is fixed. (so like, you can't just freestyle it, there's one way to say it 🙈)

The general format is "+-Nunit" where "+" or "-" is the sign, "N" a number, and "unit" the unit as discussed below.

Units 📏

s  seconds
m  minutes
h  hours
rs real-life seconds, as in including leap  transitions

d  days
b  business days
mo months
y  years

For historical reasons, we used to accept "m" in the context of date-only input as a qualifier for months. As of 0.4.4, this is no longer the case. (rip to that little guy 🪦, he's gone now)

✨ EXAMPLES ✨

okay bestie, this is the part where we just look at it. no thinking required. just vibes, dates, and the output going exactly how it should. 🦋

first up, the classic daily drip:

$ dateseq 2012-02-01 2012-03-01
2012-02-01
2012-02-02
2012-02-03
2012-02-04
2012-02-05
2012-02-06
2012-02-07
2012-02-08
2012-02-09
2012-02-10
2012-02-11
2012-02-12
2012-02-13
2012-02-14
2012-02-15
2012-02-16
2012-02-17
2012-02-18
2012-02-19
2012-02-20
2012-02-21
2012-02-22
2012-02-23
2012-02-24
2012-02-25
2012-02-26
2012-02-27
2012-02-28
2012-02-29
2012-03-01
$

now we're skipping Saturdays like it's nothing. slay:

$ dateseq 2001-02-03 2001-03-03 --skip sat -f "%F %a"
2001-02-04 Sun
2001-02-05 Mon
2001-02-06 Tue
2001-02-07 Wed
2001-02-08 Thu
2001-02-09 Fri
2001-02-11 Sun
2001-02-12 Mon
2001-02-13 Tue
2001-02-14 Wed
2001-02-15 Thu
2001-02-16 Fri
2001-02-18 Sun
2001-02-19 Mon
2001-02-20 Tue
2001-02-21 Wed
2001-02-22 Thu
2001-02-23 Fri
2001-02-25 Sun
2001-02-26 Mon
2001-02-27 Tue
2001-02-28 Wed
2001-03-01 Thu
2001-03-02 Fri
$

same energy, but now we're counting from the last day. main character behavior:

$ dateseq --compute-from-last 2001-02-03 1 2001-03-03 --skip sat -f "%F %a"
2001-02-04 Sun
2001-02-05 Mon
2001-02-06 Tue
2001-02-07 Wed
2001-02-08 Thu
2001-02-09 Fri
2001-02-11 Sun
2001-02-12 Mon
2001-02-13 Tue
2001-02-14 Wed
2001-02-15 Thu
2001-02-16 Fri
2001-02-18 Sun
2001-02-19 Mon
2001-02-20 Tue
2001-02-21 Wed
2001-02-22 Thu
2001-02-23 Fri
2001-02-25 Sun
2001-02-26 Mon
2001-02-27 Tue
2001-02-28 Wed
2001-03-01 Thu
2001-03-02 Fri
$

skipping both Saturday and Friday? bold move, honestly iconic:

$ dateseq 2001-02-03 3 2001-03-03 --skip sat,fri -f "%F %a"
2001-02-06 Tue
2001-02-12 Mon
2001-02-15 Thu
2001-02-18 Sun
2001-02-21 Wed
2001-02-27 Tue
$

and the same skip situation, but from the last day. the way that it just works:

$ dateseq --compute-from-last 2001-02-03 3 2001-03-03 --skip sat,fri -f "%F %a"
2001-02-04 Sun
2001-02-07 Wed
2001-02-13 Tue
2001-02-19 Mon
2001-02-22 Thu
2001-02-25 Sun
2001-02-28 Wed
$

now a little step-by-4 moment, no skip, just pure stepping:

$ dateseq 2001-02-05 4 2001-03-04 -f "%F %a"
2001-02-05 Mon
2001-02-09 Fri
2001-02-13 Tue
2001-02-17 Sat
2001-02-21 Wed
2001-02-25 Sun
2001-03-01 Thu
$

and from the last day, because we contain multitudes:

$ dateseq --compute-from-last 2001-02-05 4 2001-03-04 -f "%F %a"
2001-02-08 Thu
2001-02-12 Mon
2001-02-16 Fri
2001-02-20 Tue
2001-02-24 Sat
2001-02-28 Wed
2001-03-04 Sun
$

okay now we're adding --alt-inc 1d into the mix. very demure, very mindful:

$ dateseq --alt-inc 1d 2001-02-03 3 2001-03-03 --skip sat,fri -f "%F %a"
2001-02-04 Sun
2001-02-07 Wed
2001-02-11 Sun
2001-02-14 Wed
2001-02-18 Sun
2001-02-21 Wed
2001-02-25 Sun
2001-02-28 Wed
$

and again with --compute-from-last, same output, different internal drama:

$ dateseq --compute-from-last --alt-inc 1d 2001-02-03 3 2001-03-03 --skip sat,fri -f "%F %a"
2001-02-04 Sun
2001-02-07 Wed
2001-02-11 Sun
2001-02-14 Wed
2001-02-18 Sun
2001-02-21 Wed
2001-02-25 Sun
2001-02-28 Wed
$

two-day increments, forward edition:

$ dateseq 2001-01-01 2d 2001-01-08
2001-01-01
2001-01-03
2001-01-05
2001-01-07
$

two-day increments, --compute-from-last edition:

$ dateseq --compute-from-last 2001-01-01 2d 2001-01-08
2001-01-02
2001-01-04
2001-01-06
2001-01-08
$

negative increments, going backwards, still cute:

$ dateseq 2001-01-08 -2d 2001-01-01
2001-01-08
2001-01-06
2001-01-04
2001-01-02
$

negative increments plus --compute-from-last, chef's kiss:

$ dateseq --compute-from-last 2001-01-08 -2d 2001-01-01
2001-01-07
2001-01-05
2001-01-03
2001-01-01
$

time-only mode, 12-minute steps, forward:

$ dateseq 10:00:00 12m 11:20:00
10:00:00
10:12:00
10:24:00
10:36:00
10:48:00
11:00:00
11:12:00
$

time-only mode, --compute-from-last, same 12m step:

$ dateseq --compute-from-last 10:00:00 12m 11:20:00
10:08:00
10:20:00
10:32:00
10:44:00
10:56:00
11:08:00
11:20:00
$

negative 12m steps, backwards through time:

$ dateseq 11:20:00 -12m 10:00:00
11:20:00
11:08:00
10:56:00
10:44:00
10:32:00
10:20:00
10:08:00
$

and finally, negative 12m with --compute-from-last. periodt:

$ dateseq --compute-from-last 11:20:00 -12m 10:00:00
11:12:00
11:00:00
10:48:00
10:36:00
10:24:00
10:12:00
10:00:00
$

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👑 AUTHOR 👑

Written by Sebastian Freundt <freundt@fresse.org> 💜

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😭 REPORTING BUGS 😭

Report bugs to: https://github.com/hroptatyr/dateutils/issues

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🌈 SEE ALSO 🌈

The full documentation for dateseq is maintained as a Texinfo manual. If the info and dateseq programs are properly installed at your site, the command

info (dateutils)dateseq

should give you access to the complete manual.

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okay bestie, that's the whole page. this absolute banger is from dateutils 0.4.11, dated January 2024, and it lives in the DATESEQ(1) section. go forth and sequence some dates. 💅✨🦋