ps -ef | grep sleep
    root 25610 13616  0 11:17:02 pts/1    0:00 /bin/perl -w ./sleep.pl
    root 25625 25610  0 11:17:07 pts/1    0:00 sleep 12
    root 25614 25610  0 11:17:02 pts/1    0:00 sleep 11
    root 25613 25610  0 11:17:02 pts/1    0:00 sleep 15
    root 25634 25610  0 11:17:12 pts/1    0:00 /bin/perl -w ./sleep.pl
    root 25636 17134  0 11:17:13 pts/2    0:00 grep sleep