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perl script to rationalize /etc/groups

Hi all,

I am trying to write a simple perl script to optimize my /etc/groups, to make sure that it doesn't contain any members that don't have corresponding /etc/passwd entries.

here's what I have so far, but it all seems a little cumbersome:

Code:

#!/usr/local/bin/perl



open(F, "/etc/passwd");

@passwd = <F>;

chop(@passwd);

open(F, "/etc/group");

@group = <F>;

chop(@group);



for ($i=0; $i<$#group; $i++) {

        $line = $group[$i];

        $line =~ /^(..*):(..*):(..*):(..*)$/;

        ($group, undef, undef, $members) = ($1, $2, $3, $4);

        @members = split(/,/, $members);

        foreach $m (@members) {

                printf("%s\n", $m) unless grep(/^$m:/, @passwd);

        }

}

Is there a neater way of doing this in perl?

(PS: it needs to be in perl, as it's also for my programming class :) )

yes, you can try to use a hash:
store all the usernames in a hash, %users (values are not important, we need to keys only).
and you can write your search as: grep (! exists $users{$_}, split(/,/, $members));
Not tested, there can be other possibilities, for example using map.

1. always use -w & strict

Code:

#!/usr/bin/perl -w

use strict;

2. use 3 arg open and always close files you've opened asap (especially key ones like passwd!) and check open/close worked ok

Code:

open(KFILE, "<", "kfile.txt" ) or die "Can't open kfile: $!\n";

@passwd = <F>;

chomp(@passwd);

close(KFILE) or die "Can't close kfile: $!\n";

& prefer chomp() to chop().

http://perldoc.perl.org/
http://www.perlmonks.org/?node=Tutorials
http://www.tizag.com/perlT/index.php