in the latter case you don't need to continue the loop after you found a match. Thus I'd do it this way:

#use a flag to indicate a match

my $found = 0;

foreach (@commands_run) {
    if($_ =~m/clock/) {
        $found++;
        last;   # we have a match, exit loop
    }
}

$found ? print "\n Test -- found pattern  -- \n" 
       : print "\n Test -- did not find pattern -- \n";
[download]

of course in this case you can omit the $found ? print ...: print ..; part:

foreach (@commands_run) {
    if($_ =~m/clock/) {
        print "found pattern\n";
        last;   # we have a match, exit loop
    }
}
[download]