Introduction

Batch basics:

�         Its extension should be ".bat" or ".cmd" (i.e: "showdate.bat").

�         A comment in a batch is allowed using the "rem" command.

�         To avoid printing out batch execution on terminal, the "@" char should precede the Batch command (i.e: "@rem ..." or "@perl ...").

�         To jump from one line to another, the command "goto" needs a label as parameter (i.e: "goto end"). The label should be defined with ":" character before it (i.e: ":end").

Perl basics:

�         A Perl script line beginning with "@", means that the token afterwards is an array (i.e: "@array = (1, 2, 3);").

�         Comments under Perl begin with a "#" character.

�         A string with simple quote "'" can contain new lines characters.

Facts:

�         Batch and Perl scripts share only the "@" character.

The ActiveState solution

In directory "<perl path>\bin", you will find more than 50 batch files starting Perl Script.

Basically, the idea is to use the following structure:

In this case, the Batch part is at the beginning (between "@rem = '" and "goto endofperl", including these lines) and at the end of the file.

Problems:

�         it can't contain the "'" character, otherwise Perl will not be able to understand the command "@rem = '� ' � ';"

�         The error analysis should be done in the Batch part itself, as the "goto endofperl" erases the Perl script return-code�

Probably the best solution

Basically, the idea is to use the following structure:

The only common part used by Perl and Batch is the line "@goto ;#DOS" which means:

�         for Perl: "Do nothing with @goto" (which produces a warning if switch "-w" has been used) followed by the comment "DOS".

�         for Batch: "jump to label ;#DOS"

This way, both script are completely separated. Beside it, as the Perl call is the last batch command used, any result (return-code) returned by the Perl Script is automatically returned by the batch itself.

Problems:

�         The Perl script generates two warnings

�         "Useless use of a variable in void context at" and

�         "Name "main::goto" used only once"

�         The Perl call as described "perl -S %0 %*" is not supported under Windows 95/98/ME

Other solutions:

�         To avoid both warnings try following:

�         To be compatible both for Windows NT (NT, 2000, 2003, 2008, XP, Vista) and Windows 95/98/ME, use:

Tests solution

I was very sceptic with the Perl's "-S" switch. I thought we needed to specify the extension and it will not work with full path script. Therefore I tried following script (stored under "c:\apps\bat\testperl.bat", "c:\apps\bat" being set in the Path):

And tried following calls:

�         Calling "c:\apps\bat\testperl.bat param1 param2 param3" returns:

�         Calling "testperl.bat param1 param2 param3" returns:

�         Calling "testperl param1 param2 param3" returns:

�         Renaming "testperl.bat" by "test perl.bat" and calling
" "test perl" param1 param2 param3" returns:

�         Even "TESTPE~1.BAT param1 param2 param3" returns:

Now let's check some error cases:

�         When Perl works fine,"echo %errorlevel%" returns then:

�         Perl is not in the Path or not installed:

�         change "@perl -S %0 %*" with "@XXXperl ‑S %0 %*"

�         This returns:

�         "echo %errorlevel%" returns then:

�         When Perl script has troubles:

�         change back "@XXXperl ‑S %0 %*" with "@perl -S %0 %*"

�         insert a new line "print 1/0;" before line "__END__":

�         This returns:

�         "echo %errorlevel%" returns then:

�         When Perl script returns an exit code:

�         replace "print 1/0;" with "exit 5;":

�         This returns:

�         "echo %errorlevel%" returns then: