my $re = qr/.+\-(.+)/;
$foo =~ s/$re/$1/;

##</code><code>##

$foo =~ s/.+\-(.+)/$1/;

##</code><code>##

use strict;
my $re = qr/.+\-(.+)/;

while(<DATA>){
    s/$re/$1/;
    print;
}

__DATA__
domain-comp1
domain-comp2
domain-comp3

##</code><code>##

comp1
comp2
comp3