(sorry, I didn' know this would line-wrapt)
(I realize I'm responding to an old post)
#! /bin/sh

# the shell script can be arbitrarily long

echo $SHELL
echo line filtered by pearl | perl -x $0

exit
# the previous line must not be removed

(this is a void in the script as the shell nor perl will execute)

# the following must not be removed
#! perl
# it can also be the full path of perl - the -x only looks for a #! and perl on the line though.

# the following perl script must be come last but can be arbitrarily long

while (<>) {
s/pearl/perl/;
}