@echo off
echo Hello from the DOS/Windows command interpreter
perl -x -S %0
goto batchend
#!perl
use strict;
use warnings;
print "Hello from Perl\n";
exit;
__END__
:batchend
echo Back from perl in the command interpreter

##</code><code>##

rem -- somewhere inside the big batch file --
perl -e "exit 42"
if errorlevel 43 goto noperl
if errorlevel 42 goto badperl
goto noperl
:badperl
echo Sorry, there is a foreign perl installed. Can't install.
goto fail
:noperl
rem ...
rem ... much code omitted, explained in the next step
rem ...
:fail
pause
:end

##</code><code>##

rem ...
rem (assuming this script is named setup.bat)
if exists setup.bat goto havesetup
echo Can't find myself. Can't install.
goto fail
:havesetup
rem (assuming our perl.exe is in a bin subdirectory)
if not exists perl.exe goto dirsok
echo ZIP file was unpacked without directories. Can't install.
goto fail
:dirsok
if exists bin\perl.exe goto haveperl
echo Missing my perl.exe. Archive damaged? Can't install.
goto fail
:haveperl
rem ...
rem ... use perl to bootstrap itself
rem ...
:fail
pause
:end

##</code><code>##

rem ...
bin\perl.exe -e "exit($]!=5.014002)"
if not errorlevel 1 goto perlok
echo Unexpected perl interpreter found. Won't install.
goto fail
:perlok
rem ...
:fail
pause
:end

##</code><code>##

rem ...
perl -x -S %0
if errorlevel 1 goto fail
goto end
rem -- command shell will never try to interpret this or the following lines up to the fail label.
#!perl
use strict;
use warnings;
use lib 'lib';
use My::Custom::Setup;
My::Custom::Setup->run();
__END__
rem ^-- perl stops interpreting at __END__
:fail
pause
end

##</code><code>##

#!perl
use strict;
use warnings;

if (eval q[
    use lib 'lib';
    use My::Custom::Setup;
    My::Custom::Setup->run();
    1;
]) {
    exit(0);
} else {
    my $err=$@;
    Win32::MsgBox($err,MB_ICONSTOP,"Error");
    die $err;
}
__END__