[perl] How do I include a Perl module that's in a different directory?

How do I include a Perl module that's in a different directory? It needs to be a relative path from the module that's including it.

I've tried

push ( @INC,"directory_path/more_path");

also

push ( @INC,"directory_path\\more_path");

I'm surprised nobody has mentioned it before, but FindBin::libs will always find your libs as it searches in all reasonable places relative to the location of your script.

#!/usr/bin/perl
use FindBin::libs;
use <your lib>;

From perlfaq8:

How do I add the directory my program lives in to the module/library search path?

(contributed by brian d foy)

If you know the directory already, you can add it to @INC as you would for any other directory. You might use lib if you know the directory at compile time:

use lib $directory;

The trick in this task is to find the directory. Before your script does anything else (such as a chdir), you can get the current working directory with the Cwd module, which comes with Perl:

BEGIN {
    use Cwd;
    our $directory = cwd;
    }

use lib $directory;

You can do a similar thing with the value of $0, which holds the script name. That might hold a relative path, but rel2abs can turn it into an absolute path. Once you have the

BEGIN {
    use File::Spec::Functions qw(rel2abs);
    use File::Basename qw(dirname);

    my $path   = rel2abs( $0 );
    our $directory = dirname( $path );
    }

use lib $directory;

The FindBin module, which comes with Perl, might work. It finds the directory of the currently running script and puts it in $Bin, which you can then use to construct the right library path:

use FindBin qw($Bin);

Most likely the reason your push did not work is order of execution.

use is a compile time directive. You push is done at execution time:

push ( @INC,"directory_path/more_path");
use Foo.pm;  # In directory path/more_path

You can use a BEGIN block to get around this problem:

BEGIN {
    push ( @INC,"directory_path/more_path");
}
use Foo.pm;  # In directory path/more_path

IMO, it's clearest, and therefore best to use lib:

use lib "directory_path/more_path";
use Foo.pm;  # In directory path/more_path

See perlmod for information about BEGIN and other special blocks and when they execute.

Edit

For loading code relative to your script/library, I strongly endorse File::FindLib

You can say use File::FindLib 'my/test/libs'; to look for a library directory anywhere above your script in the path.

Say your work is structured like this:

   /home/me/projects/
    |- shared/
    |   |- bin/
    |   `- lib/
    `- ossum-thing/
       `- scripts 
           |- bin/
           `- lib/

Inside a script in ossum-thing/scripts/bin:

use File::FindLib 'lib/';
use File::FindLib 'shared/lib/';

Will find your library directories and add them to your @INC.

It's also useful to create a module that contains all the environment set-up needed to run your suite of tools and just load it in all the executables in your project.

use File::FindLib 'lib/MyEnvironment.pm'

'use lib' can also take a single string value...

#!/usr/bin/perl
use lib '<relative-path>';
use <your lib>;

I'll tell you how it can be done in eclipse. My dev system - Windows 64bit, Eclipse Luna, Perlipse plugin for eclipse, Strawberry pearl installer. I use perl.exe as my interpreter.

Eclipse > create new perl project > right click project > build path > configure build path > libraries tab > add external source folder > go to the folder where all your perl modules are installed > ok > ok. Done !