Converting from to unix time

I write this because I always forget the right formats, options...

BSD Date - Mac OSX

The f option is for input format. The j option is to not try to set the time. The last argument is optional, is the output format and it requires an x as a prefix.

• Convert to unix time

  $ date -jf "%Y-%m-%d %H:%M:%S %Z" "2013-07-19 00:00:01 JST" "+%s"
  1374159601
  

• Convert from unix time

  $ date -jf "%s" 1374159601 "+%Y-%m-%d %H:%M:%S %Z"
  2013-07-19 00:00:01 JST
  

  Also:

  $ date -jf "%s" 1374159601
  Fri Jul 19 00:00:01 JST 2013
  

GNU Date - Linux, etc

The -d is for the input date. Format is recognized automatically. The last parameter, same as BSD Date, is the output format (optional). It must be prepended by a +.

• Convert to unix time

  $ date -d "2013-07-19 00:00:00 JST" "+%s"
  1374159600
  

• Convert from unix time

  $ date -d @1374159600 "+%Y-%m-%d %H:%M:%S %Z"
  2013-07-19 00:00:00 JST
  

  Also :

  $ date -d @1374159600
  Fri Jul 19 00:00:00 JST 2013