%CFG = (
    'servers' => {
        'SRV1' => {
            'IP'     => 99.32.4.0,
            'user'   => 'aname',
            'pswd'   => 'p4ssw0rd',
            'status' => 'unavailable'
        },
        'SRV2' => {
            'IP'     => 129.99.10.5
            'user'   => 'guest',
            'pswd'   => 'guest'
            'status' => 'unavailable'
        }
    },
    'timeout' => 60,
    'log' => {
        'file'  => '/var/log/my_log.log',
        'level' => 'warn',
    },
    'temp' => 'remove me'
);

##</code><code>##

# Read a configuration file
#   The arg can be a relative or full path, or
#   it can be a file located somewhere in @INC.
sub ReadCfg
{
    my $file = $_[0];

    our $err;

    {   # Put config data into a separate namespace
        package CFG;

        # Process the contents of the config file
        my $rc = do($file);

        # Check for errors
        if ($@) {
            $::err = "ERROR: Failure compiling '$file' - $@";
        } elsif (! defined($rc)) {
            $::err = "ERROR: Failure reading '$file' - $!";
        } elsif (! $rc) {
            $::err = "ERROR: Failure processing '$file'";
        }
    }

    return ($err);
}

# Get our configuration information
if (my $err = ReadCfg('my_cfg.cfg')) {
    print(STDERR $err, "\n");
    exit(1);
}

##</code><code>##

# Add last access time
$CFG::CFG{'servers'}{'SRV1'}{'last_access'} = time();

# Change server availablility
$CFG::CFG{'servers'}{'SRV1'}{'status'} = 'online';

# Delete temporary data
delete($CFG::CFG{'temp'});

# Open log file
my $LOG;
if (! open($LOG, "> $CFG::CFG{'log'}{'file'}")) {
    print(STDERR "ERROR: Failure opening log file: $!\n");
    exit(1);
}

##</code><code>##

use Data::Dumper;

# Save configuration data
#   Use the same arg as used with ReadCfg()
#   so that file can be found in the %INC.
sub SaveCfg
{
    my $file = $INC{$_[0]};

    my $CFG;
    if (! open($CFG, "> $file")) {
        return ("ERROR: Failure opening '$file' - $!");
    }

    print $CFG <<_MARKER_;
#####
#
# My configuration file
#
#####

use strict;
use warnings;

our (%CFG);

# The configuration data
@{[Data::Dumper->Dump([\%CFG::CFG], ['*CFG'])]}
1;
# EOF
_MARKER_

    close($CFG);
    return (undef);   # Success
}

# Save our configuration file
if (my $err = SaveCfg('my_cfg.cfg')) {
    print(STDERR $err, "\n");
    exit(1);
}

##</code><code>##

perl -c my_cfg.cfg