How can I get the absolute path of my Perl program from its relative path?

Question

I need to find the full path to the Perl script I'm currently running, i.e.

• for ~/dir/my.pl I would need it to be "/home/user/dir/my.pl". The $0 will give me "~/dir/my.pl".

• for ./my.pl I would still need "/home/user/dir/my.pl"

etc. Thanks!

Answer 1

Use the FindBin module:

$ cat /tmp/foo/bar/baz/quux/prog
#! /usr/bin/perl

use FindBin;

print "$FindBin::Bin/$FindBin::Script\n";

$ PATH=/tmp/foo/bar/baz/quux prog
/tmp/foo/bar/baz/quux/prog

$ cd /tmp/foo/bar/baz/quux

$ ./prog 
/tmp/foo/bar/baz/quux/prog

Answer 2

It sounds like you're looking for the rel2abs function in File::Spec. For example:

#!/usr/bin/perl

use File::Spec;
my $location = File::Spec->rel2abs($0);
print "$location\n";

This will resolve $0 in the way you describe:

$ ./myfile.pl
/Users/myname/myfile.pl
$ ~/myfile.pl
/Users/myname/myfile.pl

Alternatively, you could use Cwd::abs_path in the exact same way.

Answer 3

You should take a look at FindBin or FindBin::Real.

Answer 4

Looks like you just need to expand the paths to their absolute values. Check this article for how to do that.

Answer 5

Use FindBin Module

Answer 6

Many of the concepts mentioned will break in case that the file itself is a symbolic link. I usually start my scripts in the following way:

use strict;
use English;
use warnings;

use Cwd qw(realpath);
use File::Basename;
use lib &File::Basename::dirname(&Cwd::realpath($PROGRAM_NAME));

Hopefully this helps.