#!/usr/bin/perl -w
use strict;

while (<DATA>) {

        chomp;
        print;
        print /(?=.*foo)(?=.*bar)/s ? "\t match \n" : "\t no match \n"
+;

}


__DATA__
foo bar
bar foo
foo
bar
baz
barbazfoo
foofoobar
[download]

gives output:

foo bar  match
bar foo  match
foo      no match
bar      no match
baz      no match
barbazfoo        match
foofoobar        match
[download]

hth!

andy.

Update re jeroenes's points below:
1. I used /s to make '.' match any character, in case fsn's *real* strings weren't all in one line.
2. Yes, or even print grep /(?=.*foo)(?=.*bar)/, <DATA> ; , but I wanted to print the failed matches too. Perhaps print map{ chomp; /(?=.*foo)(?=.*bar)/?"$_ yes \n":"$_ no \n"} <DATA> ;

;)