#!/usr/bin/perl
use warnings;
use strict;

open my $fh, '<', 'log.txt' or die "cant open log.txt:$!";

my $workstations;
while (<$fh>) {
    next if /^\s*$/;
    if (/(WORKSTATION\d+)/) {
        $workstations = "$1(Line $.)";
    } elsif (/(User program exit code:\s*\d+)/) {
        print "$workstations $1(Line $.)\n";
    }
}