First it should be noted that in various situations and for various reasons you might not be able to call the debugger directly from a command line or at the outset of the program. That's okay. See section 1.3.1 for how to invoke the debugger from inside your running Python program. Also, see section 1.3.2 for how to invoke after an error is encontered and you have a traceback.
Of the many additions to the standard Python debugger, two will be
mentioned here. First, this debugger should install itself somewhere
in your command path, usually as pydb
so you don't have to
invoke it as an argument to the python
command.
Second the extended debugger supports command switches courtesy of
optparse.
In particular pydb
has the two very common options
"--help" to show what options are available and "--version"to report the version that is installed.
These two options don't require any further options. However usually you will want to give the name of a script to debug and after that you may want to pass options for this script.
Thus the general form of invoking the debugger is:
pydb
[debugger-options...] python-script [script-options...]
A detailed list of options is given next.