In something like
    print 'match' if $file =~ q|/Devel/|;
I'd be inclined to use  qr|/Devel/| or better yet  qr{ /Devel/ }xms (for various arcane reasons), or m//. But it may sometimes be useful to match directly against a string, either as a literal (but this seems rather quirky to me) or in a variable; as an example of the latter:
    my $string = <$filehandle>;
    ...
    do_something() if $something_else =~ $string;
(Of course, matching against a string read from an external source may have issues with metacharacter quoting, sanitization, etc.)

> I'd be inclined to use qr|/Devel/| or m//

single quotes have no variable interpolation

  DB<47> $s="a"

  DB<48> p "a" =~ qr($s)
1
  DB<49> p "a" =~ '$s'        # same as q()

  DB<50>
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Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}