Convert an Iso Date to Seconds Since Epoch in Linux Bash

Convert an ISO date to seconds since epoch in linux bash

With GNU date (from the GNU coreutils package), specify the date to parse with -d and seconds since epoch with %s

$ date -d"2014-02-14T12:30" +%s
1392381000

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Note that this will interpret the date to be parsed as being in your local time zone. If you want date to use a specific time zone, you must specify that, either via the variable TZ (which changes the default time zone for date), or in the date string. For UTC:

$ TZ=UTC date -d"2014-02-14T12:30" +%s
1392381000

or in the string, according to ISO 8601:

$ date -d"2014-02-14T12:30Z" +%s
1392381000

See ISO 8601 on Wikipedia for how to specify other time zones in the date string.

Commandline to convert ISO8601 time to unix timestamp

Convert ISO Date/Time to Unix timestamp

date -d 'date' +"%s"

Example

   bash-# date -d 'Fri Dec  8 00:12:50 UTC 2017' +"%s"
   bash-# 1512691970

man -a date

   -d, --date=STRING
          display time described by STRING, not 'now'

   %s     seconds since 1970-01-01 00:00:00 UTC

Convert Unix timestamp to ISO Date/Time

date -Iseconds -d @<unix timestamp>

Example

   bash-# date -Iseconds -d @1512711426
   bash-# 2017-12-07T21:37:06-0800

man -a date

   -d, --date=STRING
          display time described by STRING, not 'now'

   -I[TIMESPEC], --iso-8601[=TIMESPEC]
          output  date/time  in  ISO 8601 format.  
          TIMESPEC='date' for date only (the default), 'hours',                             
          'minutes', 'seconds', or 'ns' for date and time to the 
          indicated precision.

Awk ISO to epoch

Try using getline into a variable from a pipe instead of system

cmd="date +\%s -d "created; cmd | getline current_time

https://www.gnu.org/software/gawk/manual/html_node/Getline_002fVariable_002fPipe.html#Getline_002fVariable_002fPipe

The system command returns the exit status returned by the command that was executed as its value.
http://www.delorie.com/gnu/docs/gawk/gawk_137.html

How do I convert a ISO 8601 timestamp to a Unix timestamp using Shell?

With the date util on Unix-systems, you can do e.g.

$ date -d "2017-02-18T23:54:57+01:00" "+%s"
1285716915

The result is the Unix timestamp.

Convert timestamp to date results in time out of range error

Insert a comma:

date --iso-8601=ns -d @1606982602.015489365

Bash: date returns invalid date when I try to convert this date format to epoch

Linux supports the %d/%m/%Y format on some locales for output but not for input. Shown as

LC_ALL="es_CR" locale -c d_fmt

LC_TIME

%d/%m/%Y

Fails for input

LC_ALL="es_CR" date -d '17/08/2021 21:45'

date: invalid date '17/08/2021 21:45'

For -d switch, US format is supported so your option is to reverse %d/%m

var=$(echo '17/08/2021 21:45' | sed -re 's@([0-9]{2,2})/([0-9]{2,2})/([^/]+)@\2/\1/\3@')
date -d "${var}" +"%s"

1629247500

Alternatively

IFS='/' read -r -a array <<< "17/08/2021 21:45"
date -d "${array[1]}/${array[0]}/${array[2]}" '+%s'

1629247500

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