How to change @inc to point to a relative directory

gistfile1.pl

use File::Basename qw(dirname);
use FindBin qw($Bin);
use lib dirname($Bin) . '/lib';

See How to create a Perl Module for code reuse? by Gabor Szabo, in particular the first comment by Nigel Peck.

Say you have a perl project with executables in bin/ and modules in lib/. How do you get the executables to locate the modules?

• Line 1 imports the dirname function from File::Basename, which does what you think it does.
• Line 2 uses the FindBin module to locate the "bin" directory of the called program. It doesn't seem that that directory needs to be named bin; it's just the name of the including directory. This directory name is stored in $Bin.
• Line 3 takes the directory that includes $Bin, attaches /lib, and appends this to @INC. In other words, the sister directory to $Bin named lib.