$ date '+%s'
1339832819

$ date -d '2012-02-25' '+%s'
1330124400

$ date -d '2012-02-25 06:26:57' '+%s'
1330147617

$ date -d '02/25/12' '+%s'
1330124400

$ date -d '@1339832819'
Sat Jun 16 09:46:59 CEST 2012

$ date -d '@1339832819' '+%Y-%m-%d %H:%M:%S'
2012-06-16 09:46:59

$ getent passwd root
root:x:0:0:root:/root:/bin/bash

$ top
H

:syntax on

:se hlsearch

:nohl