GLI provides many features to make a command-suite style application very easy.
Declarative DSL for parsing global options, identifying the command, command-specific options, and arguments. See Interface for what the UI of your application will be.
Multi-level command support (e.g. git remote add), see Subcommands
Automatic help command that describes your application's commands, but also describes the options to each command. All this is formatted nicely and you don't have to do a thing (see Home for an example)
Automatic management of an "rc-style" YAML-based configuration file. See Config for how to use it.
Assistance with shell completion of your application's commands. See ShellCompletion