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dateround - Man Page

Round DATE/TIME to the next occurrence of RNDSPEC.


dateround [OPTION]...  [DATE/TIME] RNDSPEC...


Round DATE/TIME to the next occurrence of RNDSPEC.

If DATE/TIME is omitted a stream of date/times is read from stdin.

DATE/TIME can also be one of the following specials
 - `now'           interpreted as the current (UTC) time stamp
 - `time'          the time part of the current (UTC) time stamp
 - `today'         the current date (according to UTC)
 - `tomo[rrow]'    tomorrow's date (according to UTC)
 - `y[ester]day'   yesterday's date (according to UTC)

1. RNDSPECs can be month names (Jan, Feb, ...), weekday names (Sun, Mon, ...),
  numerals suffixed with y, q, mo, d, bd, h, m, or s, possibly prefixed with
  a dash (`-`) to indicate the rounding direction is downwards.

2. Suffixed RNDSPECs may additionally be prefixed with a slash (`/`) to
  indicate that rounding to a multiple of RNDSPEC is desired.
  Co-class rounding.

In the first case, rounding affects the named element in the specified date or date/time and more significant elements by setting this element to the specified value and adjusting the more significant elements such that the result is greater (younger) or equal to the input (or strictly greater when -n|--next is given) for positive values, and less (older) or equal (unless -n|--next is given) for named elements that are prefixed with dash (`-`). In either case, less significant elements, e.g. subdivisions of the named element and their subdivisions are left unchanged.

   That is     dateround 2019-01-28T12:04:00 +6
   will yield  2019-02-06T12:04:00

   Similarly   dateround -n 2019-01-28T12:04:00 -- -Oct
   will yield  2018-10-28T12:04:00

In the second case, rounding is more like rounding decimal fractions to negative infinity.  The time axis is partitioned by multiples of the named element, and the oldest date or datetime is returned that is greater (younger) (or equal if -n|--next is omitted) than the specified date or date/time, when rounding down (`-` prefix) the oldest date or datetime is returned that is less (older) than the specified date or datetime.

   That is     dateround 2019-01-28T12:04:00 /1y
   will yield  2020-01-01T00:00:00

   Similarly   dateround 2019-01-28T12:04:00 /-30m
   will yield  2019-01-28T12:00:00

The superdivision of years are millennia, i.e. there's 1000 years, 500 biennia, 100 decades, etc. in a millenium.

Multiple RNDSPECs are evaluated left to right.

Note that rounding isn't commutative, e.g. dateround 2012-03-01 Sat Sep -> 2012-09-03 vs. dateround 2012-03-01 Sep Sat -> 2012-09-01

Note that non-numeric strings prefixed with a `-' conflict with the command line options and a separating `--' has to be used.

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.

-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.


Format results according to LOCALE, this would only affect month and weekday names.


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.


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.

-n,  --next

Always round to a different date or time.

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.

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


  %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.

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.

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.

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


  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.


  $ dateround 2012-03-01 2
  $ dateround -n 2012-03-01 1
  $ dateround 17:05:00 5m
  $ dateround 17:04:00 /5m
  $ dateround -n 17:04:00 4m
  $ dateround -n 17:04:00 /1m


Written by Sebastian Freundt <freundt@fresse.org>

Reporting Bugs

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

See Also

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

info (dateutils)dateround

should give you access to the complete manual.


May 2022 dateutils 0.4.10