magus says (in zid=1357716),

I use this for psychotic "must run anywhere" perl scripts:

#!/bin/sh
exec perl -x -S $0 ${1+"$@"} # -*-perl-*-
#!perl -w

if ($] !~ /^5\..*/) { # uh-oh. this isn't perl 5.
  foreach (split(/:/, $ENV{PATH})) { # try to find "perl5".
    exec("$_/perl5", "-x", "-S", $0, @ARGV) if (-x "$_/perl5");
  }
  # we failed. bail.
  die "Your perl is too old; I need perl 5. See the README for what to do.\n";
}

# load the real script. this is isolated in an 'eval' so perl4 won't
# choke on the perl5-isms.
eval join("\n", <DATA>);
if ($@) { die "$@"; }    
__END__
# real script goes here