From the README file for AppConfig:

    AppConfig is a Perl5 module for managing application configuration
    information. It maintains the state of any number of variables and
    provides methods for parsing configuration files and command line
    arguments.

    Variables values may be set via configuration files. Variables may be
    flags (On/Off), take a single value, or take multiple values stored as a
    a list or hash. The number of arguments a variable expects is determined
    by its configuration when defined.

WWW: https://metacpan.org/release/AppConfig