Re: Convert Shell script to Perl

[Utilitarian]

in reply to Convert Shell script to Perl

You could set the environment variables and run exec to call the script

[skrynesaver@busybox ~]$ cat ~/tmp/test.pl
#!/usr/bin/perl

$ENV{'THE_VAR'}= "This has been set in the environment of the script";
exec "$ENV{HOME}/tmp/test.sh"


[skrynesaver@busybox ~]$ cat ~/tmp/test.sh
#!/bin/bash
echo $THE_VAR

[skrynesaver@busybox ~]$ perl tmp/test.pl
This has been set in the environment of the script

[akrrs7]

I guess..I know that $ENV is similar to a hashmap and has a key and a value...

$ENV {'LIBDIR'}='$MY_XALANHOME/bin';

seems to be the correct way to set that. Please confirm. What I am not sure is - should I also set the JAVACMD as an environment variable using $ENV ? Thanks...

[Anonymous Monk]

Please confirm.

What happens when you Try It To See?

[akrrs7]

This is my current code:

use strict;
use warnings;
$ENV {'LIBDIR'}='$MY_XALANHOME/bin';
$ENV {'LOCALCLASSPATH'}='$ENV{LIBDIR}:/xalan.jar';
$ENV {'LOCALCLASSPATH'}='$ENV{LOCALCLASSPATH}:$ENV{LIBDIR}/xml-apis.ja
+r';
$ENV {'LOCALCLASSPATH'}='$ENV{LOCALCLASSPATH}:$ENV{LIBDIR}/xercesImpl.
+jar';

I've commented out the JAVACMD lines. When I run this on the cmd line say - perl a.pl this does not give me any errors. But I should be able to find these env variables in the command window - I cannot. I've also simply tried this on the command line

perl $ENV{'LIBDIR'}='C:\somefolder';

I get a message saying - 'Can't open perl script "$ENV":no such file or directory

[cdarke]

exec does not behave in the same way on Windows and UNIX, so it might be better to use system instead, which is similar on both (although there are still a few differences).

Although the latest ksh93 versions exec on the last statement within a script, I don't think that bash does.

One other thing to be aware of, environment variables on UNIX are case sensitive but on Windows are not - that can catch you out.

[akrrs7]

This is the code:

use strict;
use warnings;
$ENV {'LIBDIR'}='$MY_XALANHOME/bin';
$ENV {'LOCALCLASSPATH'}='$ENV{LIBDIR}:/xalan.jar';
$ENV {'LOCALCLASSPATH'}='$ENV{LOCALCLASSPATH}:$ENV{LIBDIR}/xml-apis.ja
+r';
$ENV {'LOCALCLASSPATH'}='$ENV{LOCALCLASSPATH}:$ENV{LIBDIR}/xercesImpl.
+jar';

When I run the perl program from the command line using - perl abc.pl - I don't get any error messages. When I run the following command from the commandline:

perl $ENV{'LIBDIR'}='C:\SOMEFOLDER';

I get a message saying - can't open perl script "$ENV": no such file or directory. I would've expected to create a new environment variable called LIBDIR with the c:\somefolder as the value ? Thanks

[Utilitarian]

Two things, you need to tell the Perl interpreter to execute the code rather than look for a file of that name and the environment variables will not be set int the parent process (your shell) only in the Perl process and its children.

So while perl -e "$ENV{LIBDIR'}='C:\SOMEFOLDER';" would create the varable, it would cease to exist when Perl exited.

[akrrs7]

I've tried the following code:

use strict;
use warnings;
$ENV {'LIBDIR'}='C:/eWorkspace/myPerlProgram';
$ENV {'LOCALCLASSPATH'}='$ENV{LIBDIR}:/xalan.jar';
$ENV {'LOCALCLASSPATH'}='$ENV{LOCALCLASSPATH}:$ENV{LIBDIR}/xml-apis.ja
+r';
$ENV {'LOCALCLASSPATH'}='$ENV{LOCALCLASSPATH}:$ENV{LIBDIR}/xercesImpl.
+jar';
system "$ENV{LIBDIR}/xalan_perl.pl"

I've then run this program from the command line to get the following message: Can't spawn "cmd.exe": No such file or directory at C:\eWorkspace\myPerlProgram\ xalan_perl.pl line 33.