Hi Perlmonks I am trying to get my head around using getopt::long and inparticular how excute a subroutine depending on if a certain command line option has a value assigned. I have read through the perl documentation re using getopt::long but I can't find any example of how to do this so I was hoping you might be able to help me please. Below is the code I have written so far: 


#!/bbs/opt/bin/csperl5.12

use strict;
no strict "refs";
use warnings;
use File::Compare;
use File::Basename;
use IO::File;
use Sys::Hostname;
use Data::Dumper;
use Tie::File;
use Encode;
use lib "/bbsrc/bin/prod/lib/site_perl";
use JSON::XS qw( decode_json );
use Getopt::Long;


sub usage {
    my $prog = basename $0;

    print <<_USAGE_END;

    Usage:: $prog -h | <tag name> | [-v] [ --validate] <Json cfg locat
+ion> <Output file location>

    --verbose    | -v    Run tool in verbose mode.
    --help    | -h    Usage information.
    --validate    | -V    Validate Json object and Validate this again
+st Json schema.
    --conf    | -c    Json object file location
    --output    | -o    Output location for nfs mount report
    --log    | -l    Output logfile location.
    --tag    | -t     Generate output file for all nfs mounts for a pa
+rticular tag.
    --mount    | -m     Specify mountpoint name for example software, 
+tools etc:
            This will generate an output file detailing all mounts tha
+t are required for the current server this tool is being executed on.
    --host    | -H    Specify a server hostname and this tool will gen
+erate a report detailing every single nfs mount that is required on t
+hat
             particular server.
_USAGE_END
}


sub getoptions {
    my %opts = qw( verbose 0 );
    Getopt::Long::Configure("bundling"); 

    unless (
        GetOptions (
        \%opts, qw[
          verbose|v
          help|h
          validate|V
          conf|c=s
          output|o=s
          log|l=s
          tag|t=s
          mount|m=s
          host|H=s
          ]
    )
      )
    {
        usage();
    exit 1;
    }

    usage(), exit 0 if $opts{help};
    if (!@ARGV) {
    print "Error:: No arguments specified to $0.\n";
    usage();
    exit 1;
    }

    return \%opts;
}



#-----------------------------------------------------------

MAIN: {
    my $opts = getoptions();
}

[download]

What I am trying to do is if the command line option --conf is specified then I want to set the value of this to $master_conf (this config file is json data that I am decoding). I have the following subroutine which I want to use to decocde this config file but I am not too sure how to set the value of --conf to $master_conf so I can then call this subroutine. Please can you help me on what I need to do here? 

sub extract_json {
    my $file = shift;
    local $/; #enable slurp
    open my $fh, "<", "$file";
    my $json = <$fh>;
    return $json;
}

my $json_data = extract_json("$master_conf");

my $decoded_json_obj = decode_json( $json_data);

[download]

In reply to Using getopt::long and how to use the value of one of the command line options in a subroutine by NewLondonPerl1

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