# instead of this:
    if ($user_name eq "")
    {
        print STDOUT "User name cannot be blank.\n";
        exit 1;
    }
# do this
    die "User name cannot be blank.\n" unless ( $user_name );
# (numerous examples of that sort)

#instead of this:
    my $out_FH="";
    if ($output_file eq "")
    {
        $out_FH = \*STDOUT;
    }
    else
    {
        unless (open OUT_FH,">$output_file")
        {
            return 0;
        }
        $out_FH=\*OUT_FH;
    }
    return $out_FH;
# do this:
    my $out_FH = ( $output_file eq "" ) ?  \*STDOUT :
      ( open( OUT_FH, ">$output_file" )) ? \*OUT_FH : undef;
    return $out_FH;

# and similarly, instead of this:
    if (!defined($conf_groups->{$ln_group}))
    {
        return 0;
    }
    return 1;
# do this:
    return ( defined( $conf_groups->{$ln_group} ));