The getopt Module

The getopt module used in Example 2-23 contains functions to extract command-line options and arguments. It can handle both short and long option formats.

The second argument specifies the short options that should be allowed. A colon (:) after an option name means that option must have an additional argument.

Example 2-23. Using the getopt Module

File: getopt-example-1.py import getopt import sys # simulate command-line invocation sys.argv = ["myscript.py", "-l", "-d", "directory", "filename"] # process options opts, args = getopt.getopt(sys.argv[1:], "ld:") long = 0 directory = None for o, v in opts: if o == "-l": long = 1 elif o == "-d": directory = v print "long", "=", long print "directory", "=", directory print "arguments", "=", args long = 1 directory = directory arguments = ['filename']

To make getopt look for long options, as in Example 2-24, pass a list of option descriptors as the third argument. If an option name ends with an equals sign (=), that option must have an additional argument.

Example 2-24. Using the getopt Module to Handle Long Options

File: getopt-example-2.py import getopt import sys # simulate command-line invocation sys.argv = ["myscript.py", "--echo", "--printer", "lp01", "message"] opts, args = getopt.getopt(sys.argv[1:], "ep:", ["echo", "printer="]) # process options echo = 0 printer = None for o, v in opts: if o in ("-e", "--echo"): echo = 1 elif o in ("-p", "--printer"): printer = v print "echo", "=", echo print "printer", "=", printer print "arguments", "=", args echo = 1 printer = lp01 arguments = ['message']