DATEADD(1)

💖 NAME 💖

okay bestie, listen up — this is the manual page for dateadd, part of the dateutils crew. what it does: Add DURATION to DATE/TIME and print 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 🦋

so basically: add DURATION to DATE/TIME, print the result, slay. but there's ~lore~ to how it picks up the pieces:

• if you leave out DATE/TIME but you did give a DURATION, it reads a whole list of DATE/TIMEs from stdin.
• if you leave out DURATION but you did give a DATE/TIME, it reads a list of DURATIONs from stdin.

durations are written like nY, nMO, nW, or nD for years, months, weeks, or days — and nH, nM, nS for hours, minutes, and seconds, where N is a possibly negative number. the unit symbols can be lower-case too (y, mo, w, d, h, m, s) and honestly the unit symbol d can just be ✨omitted✨. do with that what you will.

⚠️ NOT ME FORGETTING TO TELL YOU: duration addition is not commutative! order is the whole plot, iykyk.

2000-03-30 +1mo +1d -> 2000-05-01
2000-03-30 +1d +1mo -> 2000-04-30

recognized OPTIONs, bestie, here we go (there's a lot, hydrate first 💅):

• -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.
• -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.
• -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.
• -S, --sed-mode — Copy parts from the input before and after a matching date/time. Note that all occurrences of date/times within a line will be processed.
• -E, --empty-mode — Empty lines that cannot be parsed.
• --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.
• --from-zone=ZONE — Interpret dates on stdin or the command line as coming from the time zone ZONE.
• -z, --zone=ZONE — Convert dates printed on stdout to time zone ZONE, default: UTC.

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🌈 FORMAT SPECS 🌈

format specs in dateutils are similar to posix' strftime(). however — plot twist — because dateutils supports a Way Bigger range of calendars, it must employ different rules. noted. 📝

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)

roman numerals era, we love to see it 👑:

• %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.

ordinal girlies rise 🎀:

• %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. not a bug, a boundary. respect it.

for conformity, here's the list of calendar designators and their corresponding format string — iconic behaviour honestly:

• 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. periodt.

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 bozo, she's gone.

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🔥 EXAMPLES 🔥

here's the girlies in action, no cap:

$ 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
$

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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.

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okay that's the whole thing bestie, you're officially informed 💖 this was dateutils 0.4.11, dated November 2025, and this page is DATEADD(1) from the User Commands section. go forth and add durations, main character. ✨🦋🎀