Repeatedly issue a prompt, accept input, parse an initial prefix off
the received input, and dispatch to action methods, passing them the
remainder of the line as argument.
The optional argument is a banner or intro string to be issued before the
first prompt (this overrides the intro class member).
If the readline module is loaded, input will automatically
inherit bash-like history-list editing (e.g. Control-P
scrolls back to the last command, Control-N forward to the next
one, Control-F moves the cursor to the right non-destructively,
Control-B moves the cursor to the left non-destructively, etc.).
An end-of-file on input is passed back as the string 'EOF'.
An interpreter instance will recognize a command name "foo" if
and only if it has a method do_foo(). As a special case,
a line beginning with the character "?" is dispatched to
the method do_help(). As another special case, a line
beginning with the character "!" is dispatched to the
method do_shell() (if such a method is defined).
If completion is enabled, completing commands will be done
automatically, and completing of commands args is done by calling
complete_foo() with arguments text, line,
begidx, and endidx. text is the string prefix we
are attempting to match: all returned matches must begin with it.
line is the current input line with leading whitespace removed,
begidx and endidx are the beginning and ending indexes
of the prefix text, which could be used to provide different
completion depending upon which position the argument is in.
All subclasses of Cmd inherit a predefined do_help().
This method, called with an argument 'bar', invokes the
corresponding method help_bar(). With no argument,
do_help() lists all available help topics (that is, all
commands with corresponding help_*() methods), and also lists
any undocumented commands.
Hook method executed just before the command line is interpreted, but
after the input prompt is generated and issued. This
method is a stub in Cmd; it exists to be overridden by
subclasses.
The header to issue if the help output has a section for miscellaneous
help topics (that is, there are help_*() methods without
corresponding do_*() methods).
The header to issue if the help output has a section for undocumented
commands (that is, there are do_*() methods without
corresponding help_*() methods).
A flag, defaulting to true. If true, cmdloop() uses
raw_input() to display a prompt and read the next command;
if false, sys.stdout.write() and
sys.stdin.readline() are used. (This means that by
importing readline, on systems that support it, the
interpreter will automatically support Emacs-like line editing
and command-history keystrokes.)