×


Related to administration


10 Most Useful Ubuntu Linux Commands

This article covers some useful Linux commands to help you get started with working efficiently with Linux system. When operating a Linux OS, you need to use a shell — an interface that gives you access to the operating system’s services. Most Linux distributions use a graphic user interface (GUI) as their shell, mainly to provide ease of use for their users.

That being said, it's recommended to use a command-line interface (CLI) because it’s more powerful and effective. Tasks that require a multi-step process through GUI can be done in a matter of seconds by typing commands into the CLI.


How to use the cd command in Linux ?

To navigate through the Linux files and directories, use the cd command. It requires either the full path or the name of the directory, depending on the current working directory that you're in.

There are some shortcuts to help you navigate quickly:

  • cd .. (with two dots) to move one directory up.
  • cd to go straight to the home folder.
  • cd- (with a hyphen) to move to your previous directory.


How does the ls command works ?

The ls command is used to view the contents of a directory. By default, this command will display the contents of your current working directory.

There are variations you can use with the ls command:

  • ls -R will list all the files in the sub-directories as well.
  • ls -a will show the hidden files.
  • ls -al will list the files and directories with detailed information like the permissions, size, owner, etc.

Enable SSH on Ubuntu 18.04 System - How to do it ?

This article covers how to install and Enable SSH service on Ubuntu 18.04 system. You can now login remotely to your server using any SSH client from Linux or Windows system. To increase security of SSH connection by Changing default SSH port to custom one on you system. Get more details about SSH server from official SSH site.

When establishing a remote connection between a client and a server, a primary concern is ensuring security. For Linux users, the best practice of accessing and managing your server remotely is through the cryptographic protocol known as Secure Shell (SSH).


How to Enable SSH on Ubuntu ?

1. To install SSH, first update the package repository cache with:

$ sudo apt-get update

2. Now install the OpenSSH software package by entering:

$ sudo apt-get install openssh-server

If prompted, type in your password and press y (yes) to permit the installation.

3. To verify the installation was successful and SSH is running use the command:

$ sudo service ssh status

The confirmation message that you are looking for is: Active: active (running).

Install Jenkins on Ubuntu 20.04 - Step by Step Process ?

This article covers how you can install Jenkins on Ubuntu OS. For further information about Jenkins, visit its official documentation.

Jenkins is an open-source automation server that can be used to easily set up continuous integration and continuous delivery (CI/CD) pipelines.

Continuous integration (CI) is a DevOps practice in which team members regularly commit their code changes to the version control repository, after which automated builds and tests are run. 

Continuous delivery (CD) is a series of practices where code changes are automatically built, tested, and deployed to production.


To install Jenkins on Ubuntu 20.04 as a standalone service:

1. Run the following commands as root or user with sudo privileges or root to install OpenJDK 11:

$ sudo apt update
$ sudo apt install openjdk-11-jdk

2. Once the installation is complete, verify it by checking the Java version:

# java -version

3. Import the GPG keys of the Jenkins repository using the following wget command:

# wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -

4. Next, add the Jenkins repository to the system with:

# sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'

5. Once the Jenkins repository is enabled, update the apt package list and install the latest version of Jenkins by typing:

# sudo apt update
# sudo apt install jenkins

6. Jenkins service will automatically start after the installation process is complete. You can verify it by printing the service status:

# systemctl status jenkins

Install and Use Docker Compose on CentOS 8 - Step by Step Process ?

This article covers how to install and use the Docker-compose on CentOS 8 system. By using the Docker-compose, you can deploy multiple Docker applications with container services through a single command. 

Basically, Docker Compose is a tool that can be used to define and run multiple containers as a single service. With Docker Compose, you can link multiple containers and deploy an application from a single command. 

It is mainly used in the development, testing and staging environment. 

Docker Compose uses a YAML file to define a complex stack in a file and running it with a single command.


To install Docker on CentOS:

1. Before starting, make sure you have Docker installed on your server. If not installed, you will need to add Docker-CE repository to your system. 

You can add it with the following command:

$ dnf config-manager --add-repo=https://download.docker.com/linux/centos/docker-ce.repo

2. Once the repository is added, install the latest version of docker using the following command:

# dnf install docker-ce --nobest -y
# systemctl start docker
# systemctl enable docker

3. You can verify the docker version with the following command:

$ docker --version