Convert Unix timestamp to a date string

Is there a quick, one-liner way to convert a Unix timestamp to a date from the Unix command line?

date might work, except it's rather awkward to specify each element (month, day, year, hour, etc.), and I can't figure out how to get it to work properly. It seems like there might be an easier way — am I missing something?

Solution 1:

With GNU's date you can do:

date -d "@$TIMESTAMP"

# date -d @0
Wed Dec 31 19:00:00 EST 1969

(From: BASH: Convert Unix Timestamp to a Date)

On OS X, use date -r.

date -r "$TIMESTAMP"

Alternatively, use strftime(). It's not available directly from the shell, but you can access it via gawk. The %c specifier displays the timestamp in a locale-dependent manner.

echo "$TIMESTAMP" | gawk '{print strftime("%c", $0)}'

# echo 0 | gawk '{print strftime("%c", $0)}'
Wed 31 Dec 1969 07:00:00 PM EST

Solution 2:

date -d @1278999698 +'%Y-%m-%d %H:%M:%S' Where the number behind @ is the number in seconds

Solution 3:

This solution works with versions of date which do not support date -d @. It does not require AWK or other commands. A Unix timestamp is the number of seconds since Jan 1, 1970, UTC so it is important to specify UTC.

date -d '1970-01-01 1357004952 sec UTC'
Mon Dec 31 17:49:12 PST 2012

If you are on a Mac, then use:

date -r 1357004952

Command for getting epoch:

date +%s
1357004952

Credit goes to Anton: BASH: Convert Unix Timestamp to a Date

Solution 4:

As @TomMcKenzie says in a comment to another answer, date -r 123456789 is arguably a more common (i.e. more widely implemented) simple solution for times given as seconds since the Unix Epoch, but unfortunately there's no universal guaranteed portable solution.

The -d option on many types of systems means something entirely different than GNU Date's --date extension. Sadly GNU Date doesn't interpret -r the same as these other implementations. So unfortunately you have to know which version of date you're using, and many older Unix date commands don't support either option.

Even worse, POSIX date recognizes neither -d nor -r and provides no standard way in any command at all (that I know of) to format a Unix time from the command line (since POSIX Awk also lacks strftime()). (You can't use touch -t and ls because the former does not accept a time given as seconds since the Unix Epoch.)

Note though The One True Awk available direct from Brian Kernighan does now have the strftime() function built-in as well as a systime() function to return the current time in seconds since the Unix Epoch), so perhaps the Awk solution is the most portable.

Solution 5:

If you find the notation awkward, maybe the -R-option does help. It outpouts the date in RFC 2822 format. So you won't need all those identifiers: date -d @1278999698 -R. Another possibility is to output the date in seconds in your locale: date -d @1278999698 +%c. Should be easy to remember. :-)