You have many options. Let's assume you put your program specific modules in a directory lib/ below your current program directory.

The most common option is to use the lib pragma:

use lib 'lib';
[download]

You can also do yourself what the lib pragma does:

BEGIN { unshift @INC, 'lib' };
[download]

You can also change the environment variable that Perl looks at for additional include directories:

# in the shell script that starts your program:
PERL5LIB=/home/vvh/program/lib
export PERL5LIB
perl -w /home/vvh/program/program.pl $*
[download]

Or you can start Perl with the -I parameter to specify the additional include directory:

# in the shell script that starts your program:
perl -w -I/home/vvh/program/lib /home/vvh/program/program.pl $*
[download]