readline_completion_function Registers a completion function &reftitle.description; boolreadline_completion_function callablefunction This function registers a completion function. This is the same kind of functionality you'd get if you hit your tab key while using Bash. &reftitle.parameters; function You must supply the name of an existing function which accepts a partial command line and returns an array of possible matches. &reftitle.returnvalues; &return.success;