create copy of div using jquery

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July 24, 2021 in Tips and Tricks

create copy of div using jquery

<div class="container">
  <div class="goodbye">
    Goodbye
    <div class="hello">Hello</div>
  </div>
</div>
$( ".hello" ).clone().appendTo( ".goodbye" );

<div class="container">
  <div class="hello">Hello</div>
  <div class="goodbye">
    Goodbye
    <div class="hello">Hello</div>
  </div>
</div>

July 24, 2021 in Tips and Tricks

Function to optimize website

/*****Function to optimize website*****/

function remove_cssjs_ver( $src ) {
if( strpos( $src, '?ver=' ) )
 $src = remove_query_arg( 'ver', $src );
return $src;
}
add_filter( 'style_loader_src', 'remove_cssjs_ver', 10, 2 );
add_filter( 'script_loader_src', 'remove_cssjs_ver', 10, 2 );

remove_action( 'wp_head', 'rsd_link' ) ;

remove_action('wp_head', 'print_emoji_detection_script', 7);
remove_action('wp_print_styles', 'print_emoji_styles');
remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
remove_action( 'admin_print_styles', 'print_emoji_styles' );

remove_action('wp_head', 'wp_shortlink_wp_head', 10, 0);

function disable_embed(){
wp_dequeue_script( 'wp-embed' );
}
add_action( 'wp_footer', 'disable_embed' );

add_filter('xmlrpc_enabled', '__return_false');

remove_action( 'wp_head', 'wp_generator' ) ;

remove_action( 'wp_head', 'wlwmanifest_link' ) ;

function disable_pingback( &$links ) {
 foreach ( $links as $l => $link )
 if ( 0 === strpos( $link, get_option( 'home' ) ) )
 unset($links[$l]);
}
add_action( 'pre_ping', 'disable_pingback' );

add_action( 'init', 'stop_heartbeat', 1 );
function stop_heartbeat() {
wp_deregister_script('heartbeat');
}

July 24, 2021 in Tips and Tricks, Ubuntu

how to check zombie process in ubuntu

Find the zombie

$ ps aux | grep 'Z'

What you get is Zombies and anything else with a Z in it, so you will also get the grep:

USER       PID     %CPU %MEM  VSZ    RSS TTY      STAT START   TIME COMMAND
usera      13572   0.0  0.0   7628   992 pts/2    S+   19:40   0:00 grep --color=auto Z
usera      93572   0.0  0.0   0      0   ??       Z    19:40   0:00 something

Find the zombie’s parent:

$ pstree -p -s 93572

Will give you:

init(1)---cnid_metad(1311)---cnid_dbd(5145)

kill process ubuntu

sudo kill -9 process_id

$ sudo kill -1 7667
$ sudo kill -9 1317

Kill all processes you can kill.

 $ sudo  kill -9 -1

working your way up to -9

July 24, 2021 in Tips and Tricks

conntrack

Connection tracking (“conntrack”) is a core feature of the Linux kernel’s networking stack. It allows the kernel to keep track of all logical network connections or flows, and thereby identify all of the packets which make up each flow so they can be handled consistently together.

July 24, 2021 in Tips and Tricks, Ubuntu

Apache Web Server start, stop, restart methods

  1. systemctl command – Only works on systemd based Ubuntu like version 16.04 LTS and above.
  2. /etc/init.d/apache2 – A sys v init style script to start / stop / restart the Apache2 service under Debian or Ubuntu Linux.
  3. service command – This command work in most Linux distributions including Debian and Ubuntu.
  4. upstart command – Only works on certain version of Ubuntu.
  5. apache2ctl command – This method should work on all Linux and Unix like operating systems.

Method #1: systemctl command examples

To start Apache 2 on Ubuntu Linux LTS 16.04 LTS or the latest systemd based Ubuntu Linux, type:
$ sudo systemctl start apache2.service
To stop Apache 2 on Ubuntu Linux LTS 16.04 LTS or the latest systemd based Ubuntu Linux, type:
$ sudo systemctl stop apache2.service
To restart Apache 2 on Ubuntu Linux LTS 16.04 LTS or the latest systemd based Ubuntu Linux, type:
$ sudo systemctl restart apache2.service
To status of start/restart/stop operation, enter:
$ journalctl -u apache2
To find out whether Apache 2 running or not, enter:
$ sudo systemctl status apache2.service
Sample session:

Method #2: /etc/init.d/apache2 command examples

You need to login as root user or use the sudo command to control Apache web-server.

Task: Start Apache 2 Server

# /etc/init.d/apache2 start
or
$ sudo /etc/init.d/apache2 start

Task: Restart Apache 2 Server

# /etc/init.d/apache2 restart
or
$ sudo /etc/init.d/apache2 restart

Task: Stop Apache 2 Server

# /etc/init.d/apache2 stop
or
$ sudo /etc/init.d/apache2 stop

Method #3: service command examples

To restart Apache 2, enter:
$ sudo service apache2 restart
To stop Apache 2, enter:
$ sudo service apache2 stop
To start Apache 2, enter:
$ sudo service apache2 start
To gracefully reload Apache 2, enter:
$ sudo service apache2 reload

Method #4: upstart command examples

The following commands only works with certian version of Ubuntu such as Ubuntu Linux LTS 12.04 and 14.04. To start Apache 2 on Ubuntu, run:
$ sudo start apache2
To stop Apache 2 on Ubuntu, run:
$ sudo stop apache2
To restart Apache 2 on Ubuntu, run:
$ sudo restart apache2
To gracefully reload Apache 2 on Ubuntu, run:
$ sudo restart apache2

Method #5: apache2ctl command examples

apache2ctl is Apache HTTP server control interface command, which can be used to stop or start web server under any Linux distribution or UNIX.
To start Apache 2 on Ubuntu, type:
$ sudo apache2ctl start
To stop Apache 2 on Ubuntu, type:
$ sudo apache2ctl stop
To restart Apache 2 on Ubuntu, type:
$ sudo apache2ctl restart
To gracefully reload Apache 2 on Ubuntu, type:
$ sudo apache2ctl graceful

July 24, 2021 in Only Happened In India, Php, Tips and Tricks, Ubuntu

www-data is safe or not

For security.

The files are not world writeable. They are restricted to the owner of the files for writing.

The web server has to be run under a specific user. That user must exist.

If it were run under root, then all the files would have to be accessible by root and the user would need to be root to access the files. With root being the owner, a compromised web server would have access to your entire system. By specifying a specific ID a compromised web server would only have full access to its files and not the entire server.

If you decide to run it under a different user ID, then that user would need to be the effective owner of the files for proper privileges. It could be confusing to have personal ownership of system-wide files to your personal account.

Creating a specific user would make it easier to recognize the files and consistent to recognize which ID to chown to new files and folders added to the site.

The Userid or Name of the owner doesn’t matter. Whatever is chosen or decided upon will have to be configured in the web server configuration files.

By default the configuration of the owner is www-data in the Ubuntu configuration of Apache2. Since that is the default configuration, you conveniently know the ownership needed for your web files. If you change it, you would have to change the files in your site to match.

Important

It’s not a good idea to have write permissions on the entire folder, the most websites (for example: wordpress, joomla and magento) needs write permission on specific folders (image upload, file upload) A better way is to give write permission on folders and do not allow script (PHP, python) execution, always check if the user is uploading the right content, example, if you website allow an user to upload an image as it avatar, check if it is an image and not a fake image with PHP script inside. And the problem to have write permissions on the website root is if someone finds an vulnerability he could use that to write a new index.php file and ‘hack’ your website.

July 24, 2021 in Tips and Tricks, Ubuntu

website enable and disable command in ubuntu

Command for enable website

$ sudo a2ensite

Your choices are: 000-default default-ssl soa-ssl soatechnology
Which site(s) do you want to enable (wildcards ok)?

$  sudo systemctl reload apache2

Command for disable website

$ sudo a2dissite

Your choices are: 000-default default-ssl soa-ssl soatechnology
Which site(s) do you want to enable (wildcards ok)? 

$  sudo systemctl reload apache2

To list all enabled virtual hosts on the web server, run the following command in a terminal.

$ apache2ctl -S

July 23, 2021 in Tips and Tricks, Ubuntu

how to prevent denial of service attack ubuntu

How to check for and stop DDoS attacks on Linux

netstat -ntu|awk '{print $5}'|cut -d: -f1 -s |cut -f1,2 -d'.'|sed 's/$/.0.0/'|sort|uniq -c|sort -nk1 -r
sudo apt-get install net-tools -y
netstat -ntu|awk '{print $5}'|cut -d: -f1 -s |cut -f1,2,3 -d'.'|sed 's/$/.0/'|sort|uniq -c|sort -nk1 -r

netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c

sudo netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n

sudo route add ADDRESS reject
sudo iptables -A INPUT -s ADDRESS/SUBNET -j DROP