perl regex for multiple matches - regex

Question

I have a file with lines similar to following:
abcd1::101:xyz1,user,user1,abcd1,pqrs1,userblah,abcd1
I want to retain strings up to last ":" and remove all occurrences of abcd1
In the end, I need to have below:
abcd1::101:xyz1,xyz2,xyz3,pqrs1,xyz4
I tried code as below, but for some reason, it is not working. So please help
the account name is "abcd1"
sub UpdateEtcGroup {
my $account = shift;
my $file = "/tmp/group";
#ARGV = ($file);
$^I = ".bak";
while (<>){
s#^($account::\d{1,$}:)$account,?#$1#g;
s/,$//; # to remove the last "," if there
print;
}
}

Answer 1

split is the tool for the job, not a regex.
Because split lets you reliably separate out the field you do want to operate on, from the ones that you don't. Like this:
#!/usr/bin/env perl
use strict;
use warnings;
my $username = 'abcd1';
while ( <DATA> ) {
my #fields = split /:/;
my #users = split ( /,/, pop ( #fields ) );
print join ( ":", #fields,
join ( ",", grep { not m/^$username$/ } #users ) ),"\n";
}
__DATA__
abcd1::101:xyz1,user,user1,abcd1,pqrs1,userblah,abcd1

Answer 2

Don't use a regular expression for this.
use strict;
use warnings;
while (<DATA>) {
chomp;
my #parts = split(/:/, $_);
$parts[-1] = join(',', grep { !/^abcd/ } split(/,/, $parts[-1]));
print join(':', #parts) . "\n";
}
__DATA__
abcd1::101:xyz1,user,user1,abcd1,pqrs1,userblah,abcd1
abcd2::102:user1,xyz2,otheruser,abcd2,pqrs1,xyz4,abcd2
Output:
abcd1::101:xyz1,user,user1,pqrs1,userblah
abcd2::102:user1,xyz2,otheruser,pqrs1,xyz4