1Getopt::Std(3pm)       Perl Programmers Reference Guide       Getopt::Std(3pm)
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NAME

6       Getopt::Std - Process single-character switches with switch clustering
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SYNOPSIS

9           use Getopt::Std;
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11           getopts('oif:');  # -o & -i are boolean flags, -f takes an argument
12                             # Sets $opt_* as a side effect.
13           getopts('oif:', \%opts);  # options as above. Values in %opts
14           getopt('oDI');    # -o, -D & -I take arg.
15                             # Sets $opt_* as a side effect.
16           getopt('oDI', \%opts);    # -o, -D & -I take arg.  Values in %opts
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DESCRIPTION

19       The "getopts()" function processes single-character switches with
20       switch clustering.  Pass one argument which is a string containing all
21       switches to be recognized.  For each switch found, if an argument is
22       expected and provided, "getopts()" sets $opt_x (where "x" is the switch
23       name) to the value of the argument.  If an argument is expected but
24       none is provided, $opt_x is set to an undefined value.  If a switch
25       does not take an argument, $opt_x is set to 1.
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27       Switches which take an argument don't care whether there is a space
28       between the switch and the argument.  If unspecified switches are found
29       on the command-line, the user will be warned that an unknown option was
30       given.
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32       The "getopts()" function returns true unless an invalid option was
33       found.
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35       The "getopt()" function is similar, but its argument is a string
36       containing all switches that take an argument.  If no argument is
37       provided for a switch, say, "y", the corresponding $opt_y will be set
38       to an undefined value.  Unspecified switches are silently accepted.
39       Use of "getopt()" is not recommended.
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41       Note that, if your code is running under the recommended "use strict
42       vars" pragma, you will need to declare these package variables with
43       "our":
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45           our($opt_x, $opt_y);
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47       For those of you who don't like additional global variables being
48       created, "getopt()" and "getopts()" will also accept a hash reference
49       as an optional second argument.  Hash keys will be "x" (where "x" is
50       the switch name) with key values the value of the argument or 1 if no
51       argument is specified.
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53       To allow programs to process arguments that look like switches, but
54       aren't, both functions will stop processing switches when they see the
55       argument "--".  The "--" will be removed from @ARGV.
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"--help" and "--version"

58       If "-" is not a recognized switch letter, getopts() supports arguments
59       "--help" and "--version".  If "main::HELP_MESSAGE()" and/or
60       "main::VERSION_MESSAGE()" are defined, they are called; the arguments
61       are the output file handle, the name of option-processing package, its
62       version, and the switches string.  If the subroutines are not defined,
63       an attempt is made to generate intelligent messages; for best results,
64       define $main::VERSION.
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66       If embedded documentation (in pod format, see perlpod) is detected in
67       the script, "--help" will also show how to access the documentation.
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69       Note that due to excessive paranoia, if
70       $Getopt::Std::STANDARD_HELP_VERSION isn't true (the default is false),
71       then the messages are printed on STDERR, and the processing continues
72       after the messages are printed.  This being the opposite of the
73       standard-conforming behaviour, it is strongly recommended to set
74       $Getopt::Std::STANDARD_HELP_VERSION to true.
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76       One can change the output file handle of the messages by setting
77       $Getopt::Std::OUTPUT_HELP_VERSION.  One can print the messages of
78       "--help" (without the "Usage:" line) and "--version" by calling
79       functions help_mess() and version_mess() with the switches string as an
80       argument.
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84perl v5.34.0                      2021-10-18                  Getopt::Std(3pm)
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