# cpython-withatomic / Doc / libgetopt.tex

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  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 \section{Standard Module \sectcode{getopt}} \stmodindex{getopt} This module helps scripts to parse the command line arguments in \code{sys.argv}. It uses the same conventions as the \UNIX{} \code{getopt()} function. It defines the function \code{getopt.getopt(args, options)} and the exception \code{getopt.error}. The first argument to \code{getopt()} is the argument list passed to the script with its first element chopped off (i.e., \code{sys.argv[1:]}). The second argument is the string of option letters that the script wants to recognize, with options that require an argument followed by a colon (i.e., the same format that \UNIX{} \code{getopt()} uses). The return value consists of two elements: the first is a list of option-and-value pairs; the second is the list of program arguments left after the option list was stripped (this is a trailing slice of the first argument). Each option-and-value pair returned has the option as its first element, prefixed with a hyphen (e.g., \code{'-x'}), and the option argument as its second element, or an empty string if the option has no argument. The options occur in the list in the same order in which they were found, thus allowing multiple occurrences. Example: \bcode\begin{verbatim} >>> import getopt, string >>> args = string.split('-a -b -cfoo -d bar a1 a2') >>> args ['-a', '-b', '-cfoo', '-d', 'bar', 'a1', 'a2'] >>> optlist, args = getopt.getopt(args, 'abc:d:') >>> optlist [('-a', ''), ('-b', ''), ('-c', 'foo'), ('-d', 'bar')] >>> args ['a1', 'a2'] >>> \end{verbatim}\ecode The exception \code{getopt.error = 'getopt error'} is raised when an unrecognized option is found in the argument list or when an option requiring an argument is given none. The argument to the exception is a string indicating the cause of the error.