Lesson 9 - Managing Packages with APT on Ubuntu

In this lesson, we will learn how to manage software packages on a Linux system using the apt tool. Managing software packages is a crucial part of maintaining and operating a system, helping you install, update, and remove software efficiently. We will learn how to use the apt-get install, apt-get update, apt-get upgrade commands and how to manage software repositories.

1. Installing and Updating Software Packages

apt-get install: Installing Software Packages

The apt-get install command is used to install new software packages on the system.

Detailed Example:

1. Install Apache2:

   sudo apt-get install apache2
   

   This command will download and install Apache2, one of the most popular web servers.

   Reading package lists... Done
   Building dependency tree       
   Reading state information... Done
   The following additional packages will be installed:
     apache2-bin apache2-data apache2-utils
   Suggested packages:
     www-browser apache2-doc apache2-suexec-pristine | apache2-suexec-custom
   The following NEW packages will be installed:
     apache2 apache2-bin apache2-data apache2-utils
   0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
   Need to get 1,720 kB of archives.
   After this operation, 6,859 kB of additional disk space will be used.
   Do you want to continue? [Y/n]
   

   Press Y and Enter to proceed with the installation.

apt-get update: Updating Package Lists

The apt-get update command is used to update the list of available packages from the software repositories.

Detailed Example:

1. Update package lists:

   sudo apt-get update
   

   This command will update the list of available software packages from the configured repositories in the /etc/apt/sources.list file.

   Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
   Get:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease [111 kB]
   Get:3 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease [98.3 kB]
   Get:4 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
   Fetched 323 kB in 2s (142 kB/s)
   Reading package lists... Done
   

apt-get upgrade: Upgrading Installed Packages

The apt-get upgrade command is used to upgrade all the installed packages to the latest version.

Detailed Example:

1. Upgrade installed packages:

   sudo apt-get upgrade
   

   This command will download and install the latest versions of all installed software packages on the system.

   Reading package lists... Done
   Building dependency tree       
   Reading state information... Done
   Calculating upgrade... Done
   The following packages will be upgraded:
     apache2 apache2-bin apache2-data apache2-utils
   4 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
   Need to get 1,320 kB of archives.
   After this operation, 1,024 B of additional disk space will be used.
   Do you want to continue? [Y/n]
   

   Press Y and Enter to proceed with the upgrade.

2. Managing Software Repositories

Software repositories are the sources from which packages are obtained. You can add, remove, and manage these repositories through the configuration file /etc/apt/sources.list.

Adding a New Repository

To add a new repository, you need to edit the /etc/apt/sources.list file or create a new file in the /etc/apt/sources.list.d/ directory.

Example:

1. Open the repository configuration file:

   sudo nano /etc/apt/sources.list
   

2. Add the following line to add a new repository:

   deb http://repository.example.com/ubuntu focal main
   

3. Save the file and update the package list:

   sudo apt-get update
   

Removing a Repository

To remove a repository, you need to delete the corresponding line in the /etc/apt/sources.list file or delete the file in the /etc/apt/sources.list.d/ directory.

Example:

1. Open the repository configuration file:

   sudo nano /etc/apt/sources.list
   

2. Delete the line corresponding to the repository you want to remove.

3. Save the file and update the package list:

   sudo apt-get update
   

Conclusion

In this lesson, you have learned how to install, update, and upgrade software packages on a Linux system using apt. You have also learned how to manage software repositories, an essential part of keeping your system updated and secure. We hope you practice these commands and apply this knowledge to your daily work tasks.