Hello Tony, On Wed, 15 Aug 2012 15:22:10 +0100 Tony Molloy <tony.molloy at ul.ie> wrote: > > Hi, > > I'm looking for a command to extract lines from a large text file, a > password file. A typical user has a username made from a letter > followed by their id-number. > > m9718508:pw:9301:840: Lynch :/home/pgstud/m9718508:/bin/bash > > So for instance if I need to extract lines where; > > the 1st field, the username begins with an m > and > the 4th field, the group contains exactly 850 > > cat passwdfile | grep ^m | grep 850 > output > > is close but fails if the value 850 appears outside the 4th field. In > the above example which should be ignored 850 appears in the username > and home directory and is therefore extracted. Something like `grep -E '^m.+:.*:.*:850:'` maybe? Regards, -- wwp -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: not available URL: <http://lists.centos.org/pipermail/centos/attachments/20120815/5297d441/attachment-0005.sig>