Jeff Zhang wrote: >On 4/3/07, Ron Johnson <ron.l.johnson@cox.net> wrote: >> >> On 04/03/07 07:39, Jeff Zhang wrote: >> [snip] >> > >> > >> > I just care about duplicated ones in column 2, if so, to delete the >> line. >> >> Does it matter which line is deleted? >> >no, have a unique column 2 and keep undeleted lines to its original format >will be ok. $ sort -u -k2 filename