Clio is an argument-parsing library designed for building elegant command-line interfaces. Argument-parsing libraries tend to be fiddly, complicated, and ugly. Clio aims for simplicity and for consistency across a range of programming languages.

Clio is implemented in:

• C
• C++
• Go
• Java
• Python

All implementations support the same core feature set:

• Long-form boolean flags with single-character shortcuts: --flag, -f.

• Long-form string, integer, and floating-point options with single-character shortcuts: --option <arg>, -o <arg>.

• Condensed short-form options: -abc <arg> <arg>.

• Automatic --help and --version flags.

• Support for list options with multiple values.

• Support for git-style command interfaces with arbitrarily-nested commands.

See the documentation for details.