Installing Jenkins on Ubuntu 16.04

First step is to add the repository key to the system.

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

Once the key is added, we will be appending the Debian package repository address to the server's sources.list:

$ echo deb https://pkg.jenkins.io/debian-stable binary/ | sudo tee /etc/apt/sources.list.d/jenkins.list

Once both steps are done, we will be running update command so that we can use apt-get in the new repository:

$ sudo apt-get update

Last step for jenkins installation is to install Jenkins and its dependencies, including Java: we need to run following command:

$ sudo apt-get install jenkins

Once jenkins is installed successfully we will b using systemctl to start Jenkins:

$ sudo systemctl start jenkins

After complete installation of jenkins, we'll visit Jenkins on its default port, 8080, using the server domain name or IP address: http://ip_address_or_domain_name:8080

There we will see "Unlock Jenkins" screen, which displays the location of the initial password

Use the terminal window, to cat command to display the password:

$ sudo cat /var/lib/jenkins/secrets/initialAdminPassword

copy the 32-character alphanumeric password from the terminal and paste it into the "Administrator password" field, then click "Continue".

After that install suggested plugins. Then your jenkins will be ready to be used. You can add users after the successful installation.