nifty command line date and time utilities; fast date calculations and conversion in the shell
Dateutils are a bunch of tools that revolve around fiddling with dates and times on the command line with a strong focus on use cases that arise when dealing with large amounts of financial data.
Dateutils are hosted primarily on github:
Below is a short list of examples that demonstrate what dateutils can do, for full specs refer to the info and man pages. For installation instructions refer to the INSTALL file.
Dateutils commands are prefixed with a
datebut otherwise resemble known unix commands for reasons of intuition. The only exception being
strptimewhich is analogous to the libc function of the same name.
strptimeCommand line version of the C function
dateaddAdd durations to dates or times
dateconvConvert dates or times between calendars
datediffCompute durations between dates or times
dategrepGrep dates or times in input streams
dateroundRound dates or times to "fuller" values
dateseqGenerate sequences of dates or times
datesortSort chronologically.
datetestCompare dates or times
datezoneConvert date/times to timezones in bulk
I love everything explained by example to get a first impression. So here it comes.
A tool mimicking seq(1) but whose inputs are from the domain of dates rather than integers. Typically scripts use something like
$ for i in $(seq 0 9); do date -d "2010-01-01 +${i} days" "+%F" done
which now can be shortened to
$ dateseq 2010-01-01 2010-01-10
with the additional benefit that the end date can be given directly instead of being computed from the start date and an interval in days. Also, it provides date specific features that would be a PITA to implement using the above seq(1)/date(1) approach, like skipping certain weekdays:
$ dateseq 2010-01-01 2010-01-10 --skip sat,sun => 2010-01-01 2010-01-04 2010-01-05 2010-01-06 2010-01-07 2010-01-08
dateseq also works on times:
$ dateseq 12:00:00 5m 12:17:00 => 12:00:00 12:05:00 12:10:00 12:15:00
and also date-times:
$ dateseq --compute-from-last 2012-01-02T12:00:00 5m 2012-01-02T12:17:00 => 2012-01-02T12:02:00 2012-01-02T12:07:00 2012-01-02T12:12:00 2012-01-02T12:17:00
A tool to convert dates between different calendric systems and/or time zones. While other such tools usually focus on converting Gregorian dates to, say, the Chinese calendar, dconv aims at supporting calendric systems which are essential in financial contexts.
To convert a (Gregorian) date into the so called ymcw representation:
$ dateconv 2012-03-04 -f "%Y-%m-%c-%w" => 2012-03-01-00
and vice versa:
$ dateconv 2012-03-01-Sun -i "%Y-%m-%c-%a" -f '%F' => 2012-03-04
where the ymcw representation means, the
%c-th
%wof the month in a given year. This is useful if dates are specified like, the third Thursday in May for instance.
dateconv can also be used to convert occurrences of dates, times or date-times in an input stream on the fly
$ dateconv -S -i '%b/%d %Y at %I:%M %P' < Remember we meet on 2012-03-03T14:30:00
and most prominently to convert between time zones:
$ dateconv --from-zone "America/Chicago" --zone "Asia/Tokyo" 2012-01-04T09:33:00 => 2012-01-05T00:33:00$ dateconv --zone "America/Chicago" now -f "%d %b %Y %T" => 05 Apr 2012 11:11:57
A tool to perform date comparison in the shell, it's modelled after
test(1)but with proper command line options.
$ if datetest today --gt 2010-01-01; then echo "yes" fi => yes
A tool to perform date arithmetic (date maths) in the shell. Given a date and a list of durations this will compute new dates. Given a duration and a list of dates this will compute new dates.
$ dateadd 2010-02-02 +4d => 2010-02-06$ dateadd 2010-02-02 +1w => 2010-02-09
$ dateadd -1d < 2001-01-04 2000-12-31
Adding durations to times:
$ dateadd 12:05:00 +10m => 12:15:00
and even date-times:
$ dateadd 2012-03-12T12:05:00 -1d4h => 2012-03-11T08:05:00
If supported by the system's zoneinfo database leap-second adjusted calculations are possible. Use the unit
rsto denote "real" seconds:
$ dateadd '2012-06-30 23:59:30' +30rs => 2012-06-30T23:59:60
as opposed to:
$ dateadd '2012-06-30 23:59:30' +30s => 2012-07-01T00:00:00
A tool to calculate the difference between two (or more) dates. This is somewhat the converse of dadd. Outputs will be durations that, when added to the first date, give the second date.
Get the number of days between two dates:
$ datediff 2001-02-08 2001-03-02 => 22
The duration format can be controlled through the
-fswitch:
$ datediff 2001-02-08 2001-03-09 -f "%m month and %d day" => 1 month and 1 day
datediff also accepts time stamps as input:
$ datediff 2012-03-01T12:17:00 2012-03-02T14:00:00 => 92580s
The
-fswitch does the right thing:
$ datediff 2012-03-01T12:17:00 2012-03-02T14:00:00 -f '%dd %Ss' => 1d 6180s
compare to:
$ datediff 2012-03-01T12:17:00 2012-03-02T14:00:00 -f '%dd %Hh %Ss' => 1d 1h 2580s
If supported by the system's zoneinfo database leap-second adjusted calculations can be made. Use the format specifier
%rSto get the elapsed time in "real" seconds:
datediff '2012-06-30 23:59:30' '2012-07-01 00:00:30' -f '%rS' => 61
A tool to extract lines from an input stream that match certain criteria, showing either the line or the match:
$ dategrep '<2012-03-01' < Feb 2012-02-28 Feb 2012-02-29 leap day
A tool to "round" dates or time stamps to a recurring point in time, like the next/previous January or the next/previous Thursday.
Round (backwards) to the first of the current month:
$ dateround '2011-08-22' -1 => 2011-08-01
Find the next Monday from the current date (today is 2016-01-08):
$ dateround today Mon => 2015-01-11
Go back to last September, then round to the end of the month:
$ dateround today -- -Sep +31d => 2015-09-30
Round a stream of dates strictly to the next month's first:
$ dateround -S -n 1 < pay cable 2012-03-01 pay gas 2012-03-01 pay rent 2012-04-01 redeem loan 2012-04-01
Round a timeseries to the next minute (i.e. the seconds part is 00) and then to the next half-past time (and convert to ISO):
$ dateround -S 0s30m -i '%d/%m/%Y %T' -f '%F %T' < 2012-03-06 14:30:00 eventA 2012-03-06 14:30:00 eventA 2012-03-06 14:30:00 eventB 2012-03-06 15:30:00 eventB
Alternatively, if you divide the day into half-hours you can round to one of those using the co-class notation:
$ dateround -S /30m -i '%d/%m/%Y %T' -f '%F %T' < 2012-03-06 14:30:00 eventA 2012-03-06 14:30:00 eventA 2012-03-06 14:30:00 eventB 2012-03-06 15:00:00 eventB
This is largely identical to the previous example except, that a full hour (being an even multiple of half-hours) is a possible rounding target.
A tool to bring the lines of a file into chronological order.
At the moment the
datesorttool depends on
sort(1)with support for fields, in particular
-tto select a separator and
-kto sort by a particular field.
$ datesort < 2009-06-03 caev="DVCA" secu="VOD" exch="XLON" xdte="2009-06-03" nett/GBX="5.2" 2010-11-17 caev="DVCA" secu="VOD" exch="XLON" xdte="2010-11-17" nett/GBX="2.85" 2011-11-16 caev="DVCA" secu="VOD" exch="XLON" xdte="2011-11-16" nett/GBX="3.05" 2012-06-06 caev="DVCA" secu="VOD" exch="XLON" xdte="2012-06-06" nett/GBX="6.47" 2013-06-12 caev="DVCA" secu="VOD" exch="XLON" xdte="2013-06-12" nett/GBX="6.92" 2013-11-20 caev="DVCA" secu="VOD" exch="XLON" xdte="2013-11-20" nett/GBX="3.53"
A tool to quickly inspect date/time values in different timezones. The result will be a matrix that shows every date-time value in every timezone:
$ datezone Europe/Berlin Australia/Sydney now 2014-06-30T05:00:00 => 2014-01-30T17:37:13+01:00 Europe/Berlin 2014-01-31T03:37:13+11:00 Australia/Sydney 2014-06-30T07:00:00+02:00 Europe/Berlin 2014-06-30T15:00:00+10:00 Australia/Sydney
The
datezonetool can also be used to obtain the next or previous DST transition relative to a given date/time:
$ datezone --next Europe/Berlin Australia/Sydney 2013-02-19 => 2013-03-31T02:00:00+01:00 -> 2013-03-31T03:00:00+02:00 Europe/Berlin 2013-04-07T03:00:00+11:00 -> 2013-04-07T02:00:00+10:00 Australia/Sydney
where the left time stamp denotes the current zone offset and the right side is the zone offset after the transition. The date/time indicates the exact moment when the transition is about to take place.
In essence
datezoneis a better
zdump(8).
A tool that brings the flexibility of
strptime(3)to the command line. While (at least GNU)
date(1)has support for output formats, it lacks any kind of support to read arbitrary input from the domain of dates, in particular when the input format is specifically known beforehand and only matching dates/times shall be considered.
With the
strptimetool reading weird dates like
Mon, May-01/2000becomes a matter of
strptime -i "%a, %b-%d/%Y" "Mon, May-01/2000" => 2000-05-01
just as you would have done in C.
Note that
strptimeactually uses the system libc's strptime routine, and for output the system's strftime routine. Input and output modifiers will therefore vary between systems.
For a portable parser/printer combination use
dateconvas described above. Its input and output format specifiers are independent of the C runtime.
In no particular order and without any claim to completeness:
Use the one that best fits your purpose. And in case you happen to like mine, vote: dateutils' openhub page