EnvAppendValue combines command line and environment var into a single argument.

EnvSetValue set flag value if CLI option/argument is unset and env var is set.

NewCommandManager instantiates a CommandManager.

CommandManager holds root command or first parent can stores group of command.

Flag holds information about a command flag.

CommandError represents a command error type.

EnvHandler defines an environment handler type to set flag's values from environment variables.

FlagError represents a flag error type.