You can use any non-alphanumeric character as the separator in a s/// or m// operator. This allows you to choose a separator which doesn't clash with the data in the string.

In this case, if you used the 'traditional' slash as the delimiter then you'd need to escape the slash that appears in the regex. By changing the separator, you don't need to do that.

You can also use 'bracketing' characters, like (, [, < or {. In that case you need to use the opposite character at the other end, like this:

s[something][else];
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This is all explained in perldoc perlop.

"Perl makes the fun jobs fun
and the boring jobs bearable" - me

What perlop doesn't tell you is that, if you put a space after the operator name, you can use alphanumeric characters as delimiters. To use the current example: ($Z = $0) =~ s z.*/zz; I also made use of this in homer.pl, with m mmm, Donuts. But please don't do this in production code! :)

To be precise (citing from perlop manpage):

• Whitespace is not a valid delimiter, and there are additional semantics associated with single quotes:

  s/PATTERN/REPLACEMENT/egimosx
   
   [ ... snip ...]
  
                 Any non-alphanumeric, non-whitespace delimiter may
                 replace the slashes.  If single quotes are used,
                 no interpretation is done on the replacement
                 string (the /e modifier overrides this, however).
                 Unlike Perl 4, Perl 5 treats backticks as normal
                 delimiters; the replacement text is not evaluated
                 as a command.  If the PATTERN is delimited by
                 bracketing quotes, the REPLACEMENT has its own
                 pair of quotes, which may or may not be bracketing
                 quotes, e.g., s(foo)(bar) or s<foo>/bar/.  A /e
                 will cause the replacement portion to be
                 interpreted as a full-fledged Perl expression and
                 eval()ed right then and there.  It is, however,
                 syntax checked at compile-time.
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• with m//, you also want to watch out not to use '?' as the delimiter, as this has a different meaning:

     ?PATTERN?
                 This is just like the /pattern/ search, except
                 that it matches only once between calls to the
                 reset() operator.  This is a useful optimization
                 when you want to see only the first occurrence of
                 something in each file of a set of files, for
                 instance.  Only ??  patterns local to the current
                 package are reset.
  
  [ ... snip ...]
  
         m/PATTERN/cgimosx
  
         /PATTERN/cgimosx
  
  [ ... snip ...]
  
                 If "/" is the delimiter then the initial m is
                 optional.  With the m you can use any pair of non-
                 alphanumeric, non-whitespace characters as
                 delimiters. This is particularly useful for
                 matching Unix path names that contain "/", to
                 avoid LTS (leaning toothpick syndrome). If "?" is
                 the delimiter, then the match-only-once rule of
                 ?PATTERN? applies.  If "'" is the delimiter, no
                 variable interpolation is performed on the
                 PATTERN.
  [download]

  This is all explained in perldoc perlop (there is no "perlops" manpage).

  Christian Lemburg
  Brainbench MVP for Perl
  http://www.brainbench.com

Thank you very much.
(Alas, perhaps I count from 1 to 10 too quickly :) )

So let's see what this does:

$z= $0; # store the name of the script in $z
$z=~ s{.*    # anything, greedy match
         /   # then a / (the last one in $z as the match is greedy)
       }{}x; # removed
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So this snippet just returns the basename of the script.

And as you see you can also use brackets like { } as delimiters, and the x modifier lets you comment the regexp.

while(<>){ #take input from STDIN

        s/\/\//\\\/\\\//g;

    print STDOUT;

    }
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Using an alternate delimiter wouldn't eliminate the need for all the forward and back slashes, but at least it would show me (or another trying to decipher the above atrocity) where the expression was delimited.

-----
"Computeri non cogitant, ergo non sunt"