#!/usr/bin/env perl
 
use warnings;
use strict;
 
open my $fh, '<', 'foo.txt' or die "Can not open file: foo.txt: $!\n";
while (<$fh>) {
    if (/^\w{3};\w/) {
        print; # or do whatever you need to do...
    }
}
close $fh or die "Can not close file: foo.txt: $!\n";