i see what youre doing here, its alright..though it should be cleaned up/refactored i think this is a bit more clear:

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

use LWP::UserAgent;
use HTTP::Request;

# --- Configuration ---
# All results save to one consistent file.
my $output_file = 'found_admin_panels.txt';

# A single, case-insensitive regex for matching keywords. Much cleaner!
my $login_keywords_regex = qr/user|login|password|clave|senha|usager|admin|sign in/i;

# A single, master list of paths to check. No more repetition.
my @base_paths = (
    'admin/', 'administrator/', 'admin1/', 'admin2/', 'admin3/', 'admin4/', 'admin5/',
    'moderator/', 'webadmin/', 'adminarea/', 'bb-admin/', 'adminLogin/', 'admin_area/',
    'panel-administracion/', 'instadmin/', 'memberadmin/', 'administratorlogin/', 'adm/',
    'admin/account', 'admin/index', 'admin/login', 'admin/admin', 'admin_area/admin',
    'admin_area/login', 'admin_area/index', 'bb-admin/index', 'bb-admin/login',
    'bb-admin/admin', 'admin/home', 'admin/controlpanel', 'admin/cp', 'cp',
    'administrator/index', 'administrator/login', 'administrator/account', 'login',
    'modelsearch/login', 'moderator', 'moderator/login', 'moderator/admin',
    'account', 'controlpanel', 'admincontrol', 'admin_login', 'panel-administracion/login',
    'adminLogin', 'admin/adminLogin', 'home', 'adminarea/index', 'adminarea/admin',
    'adminarea/login', 'panel-administracion/index', 'panel-administracion/admin',
    'modelsearch/index', 'modelsearch/admin', 'admincontrol/login', 'adm/index',
    'adm/admloginuser', 'admin2', 'admin2/login', 'admin2/index', 'siteadmin/login',
    'siteadmin/index', 'wp-login', 'wp-admin/'
);

# Map user's choice to a file extension. Easy to add more later.
my %tech_map = (
    '1' => ['php'],
    '2' => ['asp'],
    '3' => ['aspx'],
    '4' => ['cfm'],
    '5' => ['js'],
    '6' => ['cgi'],
    '7' => ['brf'],
    '8' => ['php', 'html', 'htm', 'asp'] # "Intense" scans for multiple types
);
# --- End Configuration ---


# --- Main Program ---
# Get user input
print "Enter Target (e.g., www.example.com): ";
my $site = <STDIN>;
chomp $site;

print "Save Results? (y/n): ";
my $save_choice = <STDIN>;
chomp $save_choice;

print "Target source:\n [1] php  [2] asp  [3] aspx  [4] cfm  [5] js  [6] cgi  [7] brf  [8] Intense\n: ";
my $code = <STDIN>;
chomp $code;

# Validate user's choice for technology
unless (exists $tech_map{$code}) {
    die("Invalid selection. Exiting.");
}

# Normalize the URL
$site = 'http://' . $site if $site !~ /^http:/;
$site = $site . '/' if $site !~ /\/$/;

say "\n-> Target: $site";
say "-> Searching for admin panel...";

# Generate the final list of URLs to test
my @urls_to_scan;
foreach my $ext (@{$tech_map{$code}}) {
    foreach my $path (@base_paths) {
        # Don't add an extension if the path already ends in one or is a directory
        if ($path =~ /\/$/ || $path =~ /\./) {
            push @urls_to_scan, $site . $path;
        } else {
            push @urls_to_scan, $site . $path . '.' . $ext;
        }
    }
}
# Remove duplicate URLs that might have been generated
my %seen;
@urls_to_scan = grep { !$seen{$_}++ } @urls_to_scan;

# Create a UserAgent object
my $ua = LWP::UserAgent->new;
$ua->timeout(10); # Set a reasonable timeout
$ua->agent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36");

# Loop through and scan each URL
foreach my $url (@urls_to_scan) {
    my $request  = HTTP::Request->new(GET => $url);
    my $response = $ua->request($request);

    # Check the response
    if ($response->is_success && $response->decoded_content =~ $login_keywords_regex) {
        say "[+] Found -> $url";
        if ($save_choice eq 'y') {
            save_result($url);
        }
    } else {
        print "[-] Not Found <- $url\n";
    }
}

say "\nScan complete.";
# --- End Main Program ---


# --- Subroutines ---
sub save_result {
    my ($found_url) = @_;

    # Use modern, 3-argument open with a lexical filehandle. Safer!
    open(my $fh, '>>', $output_file) or warn "Could not open file '$output_file': $!";
    say $fh $found_url;
    close $fh;
    print "    (Result saved to $output_file)\n";
}