m#this#;
s!foo!bar!;
s{this}<that>;
m!word/word/word/word!

##</code><code>##

my $sting = 'all the metachars |+*?(){}-[]^$.   ';
$regex_safe = quotemeta $string;
print "We have a match" if m/$regex_safe/;

# alternatively we can use \Q (begin quotemeta) and \E (end qm)
print "We have a match" if m/\Q$string\E/; 

# to do what you want perhaps you might use...
m!(?:[\w ]+/){3}[\w ]+!;