Clon is a library for command-line options management. It is intended to ease the creation of standalone Common Lisp applications by providing a powerful and uniform command-line options interface. The most important features of Clon are the following.

• From the application programmer's point of view: centralized command-line options specification and management, including automatic generation of help strings, conversion from command-line / defaults / fallbacks / environment variables to application-level option values, global or on-demand option retrieval, and extensibility (the programmer can define his own option types).

• From the application user's point of view: uniform command-line option syntax across all Clon applications, customization of the help strings layout (with optional ISO6429 coloring on terminals that support it), automatic completion of abbreviated option names and short/long/pack syntax.

Clon's homepage contains a lot of resources, including the manifesto, the documentation and some screenshots.