#!/usr/bin/perl

use strict;
use warnings FATAL => 'all';

my $pid = fork();
my $output;

if ($pid) {
    print "forking child.\n";
    $output = qx( lst 2>&1 );
}

waitpid ($pid, 0);
print $output;

__OUTPUT__
Use of uninitialized value in print at 2.pl line 15.
forking child.
Can't exec "lst": No such file or directory at 2.pl line 11.