DATEADD(1)

okay bestie, sit down, hydrate, because we're doing dateadd from the dateutils fam and honestly? it's giving main character energy. this is the DATEADD(1) manual page, and i'm about to make it make sense. 💖

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✨ NAME ✨

dateadd — adds a DURATION to a DATE/TIME and prints the result. that's it, that's the whole vibe. 🎀

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🦋 SYNOPSIS 🦋

dateadd [OPTION]...  [DATE/TIME] [DURATION]

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💅 DESCRIPTION 💅

okay so the whole thing is: you add DURATION to DATE/TIME and it prints the result. slay.

but here's the cute part — it's flexible like that:

• if you skip DATE/TIME but still hand over a DURATION, it reads a whole list of DATE/TIMEs from stdin. ✨
• if you skip DURATION but give it a DATE/TIME, it reads a list of DURATIONs from stdin. ✨

Durations get written as nY, nMO, nW, or nD for years, months, weeks, or days respectively — or nH, nM, nS for hours, minutes, and seconds — where N is a number that can totally be negative (yes, we love a negative number). the unit symbols can be lowercase too (y, mo, w, d, h, m, s), and the unit symbol d can just be... omitted. gone. not needed. 🫶

⚠️ not me forgetting to tell you: duration addition is not commutative! order matters, bestie, it's not a vibe where you can just swap things around: 2000-03-30 +1mo +1d -> 2000-05-01 2000-03-30 +1d +1mo -> 2000-04-30

Recognized OPTIONs, let's go:

🌈 Recognized OPTIONs 🌈

• -h, --help — prints help and dips out. 👋
• -V, --version — prints the version and dips out.
• -q, --quiet — suppresses the message about date/time and duration parser errors and fix-ups. by default it prints a warning, or the fixed-up value, and returns error code 2. so if you want silence, this is your girl.
• -f, --format=STRING — the output format. this can be either a specifier string (like strftime()'s FMT, yk) or the name of a calendar.
• -i, --input-format=STRING... — the input format, and yes you can use this multiple times. each date/time gets passed to the input format parsers in the order you gave them, and if a date/time can be read successfully with a given input format specifier string, that value gets used. first one to work wins. 💫
• -b, --base=DT — for underspecified input, use DT as a fallback to fill in the missing fields. also used for ambiguous format specifiers to position their range on the absolute time line. it must be a date/time in ISO8601 format. if you omit it, it defaults to the current date/time. no cap.
• -e, --backslash-escapes — turns on interpretation of backslash escapes in the output and input format specifier strings.
• -S, --sed-mode — copies parts from the input before and after a matching date/time. heads up: all occurrences of date/times within a line will be processed.
• -E, --empty-mode — empties out lines that can't be parsed.
• --locale=LOCALE — formats results according to LOCALE. this would only affect month and weekday names.
• --from-locale=LOCALE — interprets dates on stdin or the command line as coming from the locale LOCALE. this would only affect month and weekday names, since input formats have to be specified explicitly.
• --from-zone=ZONE — interprets dates on stdin or the command line as coming from the time zone ZONE.
• -z, --zone=ZONE — converts dates printed on stdout to time zone ZONE. default: UTC. 🌍

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🌸 FORMAT SPECS 🌸

so format specs in dateutils are similar to posix' strftime(). but — and this is the plot twist — because dateutils supports a broader range of calendars, it has to employ different rules. it's giving ✨range✨.

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

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. don't try it, she said no.

and for conformity, here's the list of calendar designators and their corresponding format string, because we're thorough like that:

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. iconic. 💫

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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 yeah, fixed syntax, no negotiating.

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 era.

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🔥 EXAMPLES 🔥

watch her work, bestie:

$ dateadd 2012-03-01 1d
2012-03-02
$

$ dateadd 2012-03-01 1mo
2012-04-01
$

$ dateadd 2012-03-31 1mo
2012-04-30
$

$ dateadd 2w2d <<EOF
2012-03-01
2012-03-02
2012-03-04
2012-03-08
2012-03-16
EOF
2012-03-17
2012-03-18
2012-03-20
2012-03-24
2012-04-01
$

$ dateadd 10:01:00 1h6m
11:07:00
$

$ dateadd 10:01:00 -1h6m
08:55:00
$

$ dateadd 10:01:00 3605s
11:01:05
$

ate. no crumbs. 👑

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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 dateadd is maintained as a Texinfo manual. if the info and dateadd programs are properly installed at your site, the command

info (dateutils)dateadd

should give you access to the complete manual. iykyk. 📖✨

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and that's the whole page, bestie 🫶 this was dateutils version 0.4.11, dated January 2024, and honestly? she's iconic for it. go forth and add durations. 💖💅🎀