Re: [CentOS] Extract lines from text file

On 08/15/2012 10:22 AM, Tony Molloy 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.

Any ideas.

Thanks,

Tony _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos

[mlapier@mushroom ~]$ cat tmpfile m9718508:pw:9301:840: Lynch :/home/pgstud/m9718508:/bin/bash m1234567:pw:9302:850: Lynch :/home/pgstud/m1234567:/bin/bash

[mlapier@mushroom ~]$ grep ^m tmpfile | grep ":850:" m1234567:pw:9302:850: Lynch :/home/pgstud/m1234567:/bin/bash [mlapier@mushroom ~]$