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Dateutils

Dateutils are a bunch of tools that revolve around fiddling with dates and times in 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 d but otherwise resemble known unix commands for reasons of intuition. The only exception being strptime which is analogous to the libc function of the same name.

  • strptime Command line version of the C function
  • dadd Add durations to dates or times
  • dconv Convert dates or times between calendars
  • ddiff Compute durations between dates or times
  • dgrep Grep dates or times in input streams
  • dround Round dates or times to “fuller” values
  • dseq Generate sequences of dates or times
  • dtest Compare dates or times
  • dzone Convert date/times to timezones in bulk

Distributions

Following Linux distros and BSD flavours provide native packages (in alphabetical order):

Changelog

See dedicated changelog page.

Examples

I love everything to be explained by example to get a first impression. So here it comes.

dseq

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

$ dseq 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:

$ dseq 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

dseq also works on times:

$ dseq 12:00:00 5m 12:17:00
=>
  12:00:00
  12:05:00
  12:10:00
  12:15:00

and also date-times:

$ dseq --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

dconv

A tool to convert dates between different calendric systems. 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:

$ dconv 2012-03-04 -f "%Y-%m-%c-%w"
=>
  2012-03-01-00

and vice versa:

$ dconv 2012-03-01-Sun -i "%Y-%m-%c-%a" -f '%F'
=>
  2012-03-04

where the ymcw representation means, the %c-th %w of the month in a given year. This is useful if dates are specified like, the third Thursday in May for instance.

dconv can also be used to convert occurrences of dates, times or date-times in an input stream on the fly

$ dconv -S -i '%b/%d %Y at %I:%M %P' <<EOF
Remember we meet on Mar/03 2012 at 02:30 pm
EOF
=>
  Remember we meet on 2012-03-03T14:30:00

and most prominently to convert between time zones:

$ dconv --from-zone "America/Chicago" --zone "Asia/Tokyo" 2012-01-04T09:33:00
=>
  2012-01-05T00:33:00

$ dconv --zone "America/Chicago" now -f "%d %b %Y %T"
=>
  05 Apr 2012 11:11:57

dtest

A tool to perform date comparison in the shell, it’s modelled after test(1) but with proper command line options.

$ if dtest today --gt 2010-01-01; then
    echo "yes"
  fi
=>
  yes

dadd

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.

$ dadd 2010-02-02 +4d
=>
  2010-02-06

$ dadd 2010-02-02 +1w
=>
  2010-02-09

$ dadd -1d <<EOF
2001-01-05
2001-01-01
EOF
=>
  2001-01-04
  2000-12-31

Adding durations to times:

$ dadd 12:05:00 +10m
=>
  12:15:00

and even date-times:

$ dadd 2012-03-12T12:05:00 -1d4h
=>
  2012-03-11T08:05:00

As of version v0.2.2 leap-second adjusted calculations are built-in. Use the unit rs to denote “real” seconds:

$ dadd '2012-06-30 23:59:30' +30rs
=>
  2012-06-30T23:59:60

as opposed to:

$ dadd '2012-06-30 23:59:30' +30s
=>
  2012-07-01T00:00:00

ddiff

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:

$ ddiff 2001-02-08 2001-03-02
=>
  22

The duration format can be controlled through the -f switch:

$ ddiff 2001-02-08 2001-03-09 -f "%m month and %d day"
=>
  1 month and 1 day

ddiff also accepts time stamps as input:

$ ddiff 2012-03-01T12:17:00 2012-03-02T14:00:00
=>
  92580s

The -f switch does the right thing:

$ ddiff 2012-03-01T12:17:00 2012-03-02T14:00:00 -f '%dd %Ss'
=>
  1d 6180s

compare to:

$ ddiff 2012-03-01T12:17:00 2012-03-02T14:00:00 -f '%dd %Hh %Ss'
=>
  1d 1h 2580s

As of version v0.2.2 leap-second adjusted calculations can be made. Use the format specifier %rS to get the elapsed time in “real” seconds:

ddiff '2012-06-30 23:59:30' '2012-07-01 00:00:30' -f '%rS'
=>
  61

dgrep

A tool to extract lines from an input stream that match certain criteria, showing either the line or the match:

$ dgrep '<2012-03-01' <<EOF
Feb	2012-02-28
Feb	2012-02-29	leap day
Mar	2012-03-01
Mar	2012-03-02
EOF
=>
  Feb	2012-02-28
  Feb	2012-02-29	leap day

dround

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:

$ dround '2011-08-22' -1
=>
  2011-08-01

Round a stream of dates strictly to the next month’s first:

$ dround -S -n 1 <<EOF
pay cable	2012-02-28
pay gas	2012-02-29
pay rent	2012-03-01
redeem loan	2012-03-02
EOF
=>
  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 full or half hour (and convert to ISO):

$ dround -S 30m -i '%d/%m/%Y %T' -f '%F %T' <<EOF
06/03/2012 14:27:12	eventA
06/03/2012 14:29:59	eventA
06/03/2012 14:30:00	eventB
06/03/2012 14:30:01	eventB
EOF
=>
  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

dsort

New in dateutils 0.3.0. A tool to bring the lines of a file into chronological order.

$ dsort <<EOF
2009-06-03 caev="DVCA" secu="VOD" exch="XLON" xdte="2009-06-03" nett/GBX="5.2"
2011-11-16 caev="DVCA" secu="VOD" exch="XLON" xdte="2011-11-16" nett/GBX="3.05"
2013-11-20 caev="DVCA" secu="VOD" exch="XLON" xdte="2013-11-20" nett/GBX="3.53"
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"
2010-11-17 caev="DVCA" secu="VOD" exch="XLON" xdte="2010-11-17" nett/GBX="2.85"
EOF
=>
  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"

At the moment the dsort tool is built upon sort(1) and cut(1).

dzone

New in dateutils 0.3.0. 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:

$ dzone 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 dzone tool can also be used to obtain the next or previous DST transition relative to a given date/time:

$ dzone --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 dzone is a better zdump(1).

strptime

A tool that brings the flexibility of strptime(3) to the command line. While 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.

Usually, to print something like Mon, May-01/2000 in ISO 8601, people come up with the most prolific recommendations like using perl or sed or awk or any two of them, or they come up with a pageful of shell code full of bashisms, and when sufficiently pestered they “improve” their variant to a dozen pages of portable shell code.

The strptime tool does the job just fine

strptime -i "%a, %b-%d/%Y" "Mon, May-01/2000"
=>
  2000-05-01

just like you would have done in C.

Timezone map files

Starting with version 0.3.0 dateutils has built-in support for tzmaps. We’ve dedicated a branch (orphan tzmaps) for their development and a website for further information.

Similar projects

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’ Ohloh page

Social Media

Yes, we’re aware of social media:

Not that there will be no substantial content though.