#! /usr/bin/env perl
use strict;
use warnings;
use Getopt::Long   qw( GetOptions );
GetOptions(
    'root=s' => \my $input_dir,
    'outdir=s' => \my $output_dir,
    'file=s' => \my $mapfile,
)


In the above i called the directory straightly from the location but my question is first i should read the project.txt file from one location and  from that project.txt file i should read the directory(i.e the line starts with REVISION_LOCATION).How can i script it using perl?