Perl Pocket Reference, 5th Edition

Environment Variables

Perl uses several environment variables. With a few exceptions, these all start with PERL. Library packages and platform-dependent features may have their own environment variables.

These are the most common environment variables:

HOME

Used if chdir has no argument.

LC_ALL, LC_CTYPE, LC_COLLATE, LC_NUMERIC, PERL_BADLANG, LANGUAGE, LANG

Controls how Perl handles data specific to particular natural languages.

LOGDIR

Used if chdir has no argument and HOME is not set.

PATH

Used in executing subprocesses, and in finding the Perl script if -S is used.

PERL5LIB

A colon-separated list of directories to search for Perl library files before looking in the standard library and the current directory.

PERLLIB

Used instead of PERL5LIB if PERL5LIB is not defined.

PERL5OPT

Initial (command-line) options for Perl.