[Richard Suchenwirth] - Tcl is the Tool Command Language. Execution is done by splitting scripts into commands (by newline or semicolon). A command is a sequence of words, the first being the command name, the rest its arguments. (So far from Tcl syntax). A specialized mantra would say "everything is a command", even what other languages call "control strucutures" (if, while, for...) or "declarations" (global, proc, variable...).

All available command names at a given time (and namespace) are returned by
 info commands
They may have come from several sources:
   * C-implemented commands
   * Tcl-implemented [proc]s, listed in ''info procs''
   * Aliases for other commands, listed in ''interp aliases {}''
   * Tk widgets use their pathname as command; you can test whether a string is a widget command with ''winfo exists $name''
   * [image]s also use their name as command name, listed in ''image names''
   * [OO] systems like [incr Tcl] also use object names in the command position

To introspect commands in other than the current namespace, walk the tree with ''[namespace] children''.