I've used -x to bundle shell scripts with Perl code, as in

#!/bin/sh

complex-pipeline-with | perl -x "$0" | while read LINE ; do
    something-with-output
done

exit 0

###################

#!/usr/bin/perl -pl
use strict;
use warnings;

# some relatively complex string mangling here
[download]

From: my@email.com
To: your@email.com
Subject: perl program

Hello here is my program
hope you like it,

Joost.


#!/usr/bin/perl -w
use strict;
print "Just another perl hacker\n";
[download]

> perl -x message.txt
Just another perl hacker
[download]

J.

randomApacheVar = 1
var2=3
<Perl>
#!perl
my $perl = 'code';
some('more','code');
#etc
__END__
</Perl>
[download]

You can do even better than that. I've seen the above technique used to create synchronized httpd.conf files, so that information that in one is maintained through mod_perl in the next has the Perl expanded out so that it can be used with a non-mod_perl Apache server. (This for a reverse proxy config, the non-mod_perl server handles all of the static requests and forwards what it needs to to the mod_perl servers.)

could you elaborate on "so that information that in one is maintained through mod_perl in the next has the Perl expanded out "? thanks

# telnet <my-development-box> <some-port> | perl -x
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On the development box I simply have an inetd server at <some-port>, that cat(1)'s the relevant setup script.

perl -x eats the telnet garbage from the front of the output.

---GreyGlass

Though I can't prove it, (without working harder than I care to on a Sunday night) I'm pretty sure the -x switch in Perl harks back to this use of patch on usenet. Not that it isn't still useful, as others have noted.

From http://search.cpan.org/src/JHI/perl-5.8.1/patchlevel.h:

In a language so well known for its rich text processing capabilities, and given that Perl scripts are textual, I would be more surprised to find this sort of feature missing, than to find of its existance.

On a commical side-note, such an embeded Perl script would come in handy for one of those Mission Impossible "This message will self-destruct in sixty seconds." dispatches. ;)