Install only Webmin without Lamp Stack

$ sudo nano /etc/apt/sources.list

$ deb http://download.webmin.com/download/repository sarge contrib

$ wget http://www.webmin.com/jcameron-key.asc 

$ sudo apt-key add jcameron-key.asc

$ sudo apt update 

$ sudo apt install webmin

Change Ubuntu server Hoatname permanently

 Type the hostnamectl command :

sudo hostnamectl set-hostname newNameHere

Delete the old name and setup new name.

Next Edit the /etc/hosts file:

sudo nano /etc/hosts

Replace any occurrence of the existing computer name with your new one.

Reboot the system to changes take effect:

sudo reboot

How to install VestaCP

# Connect to your server as root via SSH

ssh root@your.server

# Download installation script

curl -O http://vestacp.com/pub/vst-install.sh

# Run it

bash vst-install.sh

Google Sheet Sigle column No Duplicate Data Validation

 Here the example is given for column A:

=COUNTIF($A$2:$A711,$A13)<2

How to Install SQLite driver for your PHP version in Ubuntu

Log in to your web server via SSH and run the following command:

sudo apt-get install php-sqlite3

If the above command does not work, you can try the PHP version-specific instructions below:

For PHP5, use

sudo apt-get install php5-sqlite

For PHP7.0, use

sudo apt-get install php7.0-sqlite

For PHP7.1, use

sudo apt-get install php7.1-sqlite

For PHP7.2, use

sudo apt-get install php7.2-sqlite

For PHP7.3, use

sudo apt-get install php7.3-sqlite

For PHP7.4, use

Then

Restart Apache

sudo service apache2 restart

Restart Nginx

sudo service nginx restart

How to generate SSH keys in Mac OS

To generate SSH keys in Mac OS X, follow these steps:

1. Enter the following command in the Terminal window.ssh-keygen -t rsa
This starts the key generation process. When you execute this command, the ssh-keygen utility prompts you to indicate where to store the key.

2. Press the ENTER key to accept the default location. The ssh-keygen utility prompts you for a passphrase.

3. Type in a passphrase. You can also hit the ENTER key to accept the default (no passphrase). However, this is not recommended.
Please note that you will need to enter the passphrase a second time to continue.

After you confirm the passphrase, the system generates the key pair.

Your identification has been saved in /Users/user/.ssh/id_rsa.

Your public key has been saved in /Users/user/.ssh/id_rsa.pub.

The key fingerprint is:

ae:89:72:0b:85:da:5a:f4:7c:1f:c2:43:fd:c6:44:38 user@mymac.local

The key's randomart image is:

+--[ RSA 2048]----+

|                 |

|         .       |

|        E .      |

|   .   . o       |

|  o . . S .      |

| + + o . +       |

|. + o = o +      |

| o...o * o       |

|.  oo.o .        |

+-----------------+

Your private key is saved to the id_rsa file in the .ssh directory and is used to verify the public key you use belongs to the same cloud server. It's important to never share your private key with anyone, it is equivalent of your password!

Your public key is saved to the id_rsa.pub file and it is the key you'll upload to our cloud service. You can save this key to the clipboard by running this:

pbcopy < ~/.ssh/id_rsa.pub

or

cat ~/.ssh/id_rsa.pub

How to retry delivery of Postfix mail in queue?

 postsuper -r ALL && postqueue -f