Privilege users parsing script

priv.pl

#!/bin/perl
use strict;
use warnings;

use File::Spec;

our %file_path = (
    "PASSWD"  => "etc/passwd",
    "GROUP"   => "etc/group",
    "SUDOERS" => "etc/sudoers",
);

sub read_file {
    my $file = shift;
    open (FH, "< $file");
    my @lines;
    while(<FH>) {
        push @lines, $_;
    }
    close FH;
    return @lines;
}

sub parse_sudoers {
    # The only variable: BASE_PATH
    my $BASE_PATH = shift;

    # An array that holds all of the names that are found.
    my @usernames;
    my $sudoers_file = File::Spec->catfile($BASE_PATH, $file_path{SUDOERS});
    my @sudoers = read_file($sudoers_file);

    # Grab the groups and users from the sudoers file.  Make sure that the
    # 'Defaults' parameter is not injested.
    my @groups = grep(/^%/, @sudoers);
    my @users = grep(/^\w+/ && /^(?!Defaults)/, @sudoers);

    # Grab each username and throw it into @usernames
    foreach my $user (@users) {
        $user =~ /^(\w+)/;
        push @usernames, $1;
    }

    # Grab each group...
    foreach my $group (@groups) {
        $group =~ /^%(\w+)/;

        # ...find the users in that group and toss those into @usernames.
        foreach my $user (get_group_users($BASE_PATH, $1)) {
            $user =~ /^(\w+)/;
            push @usernames, $1;
        }
    }

    # Makes sure there aren't duplicates in the @usernames array.
    my %seen;
    my @unique = grep { !$seen{$_}++ } @usernames;

    # Print the users out with their associated comment.
    foreach my $user (@unique) {
        print "$user:";
        print get_user_comment($BASE_PATH, $user);
        print "\n";
    }
}

# Parse the group file, grab all of the users of $GROUP and return them as
# an array.
# get_group_users(BASE_PATH, GROUP)
sub get_group_users {
    my $BASE_PATH = shift;
    my $GROUP = shift;
    my $full_path = File::Spec->catfile($BASE_PATH, $file_path{GROUP});
    my @content = read_file($full_path);
    my @groups = grep(/^$GROUP:/, @content);
    foreach my $group (@groups) {
        my @fields = split(":", $group);
        my @users = split(",", $fields[3]);
        return @users;
    }
}

# Parse the passwd file, grab the comment field of a given user and return 
# it.
# get_user_comment(BASE_PATH, USER)
sub get_user_comment {
    my $BASE_PATH = shift;
    my $USER = shift;
    my $full_path = File::Spec->catfile($BASE_PATH, $file_path{PASSWD});
    my @passwd_content = read_file($full_path);
    my @users = grep(/^$USER:/, @passwd_content);
    foreach my $user (@users) {
        my @temp = split(":", $user);
        return $temp[4];
    }
}

parse_sudoers();