Install and remove software on Linux

To install software on Linux, a single command is enough: sudo apt install name (Debian/Ubuntu) or sudo dnf install name (RHEL/Fedora). This guide shows you how to search for, install, check and remove packages with confidence.

What you will learn

• Refresh the list of packages available
• Search for a package by name or keyword
• Install a package and check that it works
• Remove a package cleanly
• List the packages already installed

How do you refresh the package list?

Before any installation, you must refresh the list of available packages. Without this step, your system does not know the latest versions, and may not even know a package exists.

Debian / Ubuntu

sudo apt update

Expected output

Hit:1 http://archive.ubuntu.com/ubuntu noble InRelease
Get:2 http://security.ubuntu.com/ubuntu noble-security InRelease
Reading package lists... Done

This command changes nothing on your system. It only downloads the up-to-date list of available packages and versions.

RHEL / Fedora

sudo dnf check-update

DNF refreshes its metadata automatically. This command shows the packages that have a newer version available. An exit code of 100 means that updates exist: it is normal.

Get into the habit of running apt update, or dnf check-update, before each installation session. Without this refresh, your machine works on an out-of-date catalogue: it may install an outdated version, or refuse a package that is actually available with an E: Unable to locate package that seems incomprehensible.

How do you search for a package?

You do not know the exact name of the package? Use the search, which looks through names and descriptions:

Debian / Ubuntu

apt search text editor

To show the details of a package you found:

apt show vim

Output (excerpt)

Package: vim
Version: 2:9.1.0016-1ubuntu7.20
Description: Vi IMproved - enhanced vi editor

RHEL / Fedora

dnf search text editor

To show the details of a package you found:

dnf info vim-enhanced

Output (excerpt)

Name         : vim-enhanced
Version      : 9.1.083
Summary      : A version of the VIM editor which includes recent enhancements

Search in English: package descriptions are written in English, and a search in another language usually returns nothing. On Ubuntu 24.04, the French words apt search editeur texte find no result, where apt search text editor finds 96 (measured).

Remember too that the package name does not always match the software name. The Vim editor installs from vim on Debian and from vim-enhanced on RHEL, and the case is frequent as soon as a piece of software is split into several packages. That is precisely what search is for: running it before install costs a few seconds and avoids a No match for argument.

How do you install a package?

The three steps below go from the installation itself to the check that the command works, then to the package that provides it.

1. Start the installation with sudo (packages are installed in system directories that require administrator rights):

   Debian / Ubuntu

   sudo apt install tree

   APT shows the list of packages that will be installed:

   Output on Ubuntu 24.04

   The following NEW packages will be installed:
     tree
   0 upgraded, 1 newly installed, 0 to remove and 92 not upgraded.

   When only the requested package is added, APT installs it without asking. As soon as it must add dependencies, it lists them and asks for confirmation: type Y (or Enter) to accept.

   RHEL / Fedora

   sudo dnf install tree

   DNF shows a summary and asks for confirmation:

   Output on AlmaLinux 10

   Installing:
    tree    x86_64    2.1.0-8.el10    baseos
   Transaction Summary
   Install  1 Package
   Is this ok [y/N]:

   Type y to confirm.

2. Check that the installation worked:

   tree --version

   Output on Ubuntu 24.04

   tree v2.1.1 (c) 1996 - 2023 by Steve Baker, Thomas Moore, Francesc Rocher, Florian Sesser, Kyosuke Tokoro

   If the command prints a version number, the software is installed.

3. Check which package provides a command (useful when the name differs):

   Debian / Ubuntu

   dpkg -S "$(command -v tree)"

   Output

   tree: /usr/bin/tree

   RHEL / Fedora

   rpm -qf "$(command -v tree)"

   Output

   tree-2.1.0-8.el10.x86_64

Install several packages at once

You can install several packages in the same command, separated by spaces:

Debian / Ubuntu

sudo apt install wget tree htop

RHEL / Fedora

sudo dnf install wget tree

htop is left out on purpose here: on RHEL and AlmaLinux, it is not in the base repositories but in EPEL, and a single name that cannot be found makes the whole command fail (Unable to find a match: htop, measured on AlmaLinux 10). On AlmaLinux or Rocky, enable EPEL first with sudo dnf install epel-release.

How do you remove a package?

Removing is as simple as installing, but APT offers two levels: keep the configuration files or delete them too.

Debian / Ubuntu

Simple removal (keeps the configuration files):

sudo apt remove tree

Complete removal (also deletes the configuration files):

sudo apt purge tree

Check: the command must no longer be available:

tree --version

Expected output

bash: tree: command not found

RHEL / Fedora

sudo dnf remove tree

DNF removes the package and can offer to remove the dependencies that are no longer needed.

Check:

tree --version

Expected output

bash: tree: command not found

If you had run tree in the same terminal before the removal, Bash answers bash: /usr/bin/tree: No such file or directory instead: it had remembered the path of the command. The package is really gone; hash -r clears that memory.

Read the summary before confirming

Before confirming a removal, read the list of packages involved. Removing a package can bring along the removal of packages that depend on it. If the list is long or holds critical packages, answer n (no) and look for an alternative.

How do you list installed packages?

To see which software is already installed on your system, query the package database directly:

Debian / Ubuntu

dpkg -l | head -20

To check whether a given package is installed:

dpkg -l tree

RHEL / Fedora

rpm -qa | head -20

To check whether a given package is installed:

rpm -q tree

How do you reinstall a package?

If a piece of software no longer works properly, you can reinstall it without removing it first. The package files are put back in place, which repairs a deleted or damaged file:

Debian / Ubuntu

sudo apt reinstall tree

RHEL / Fedora

sudo dnf reinstall tree

Troubleshooting

These 5 symptoms cover almost every installation failure met at the start, and they have one thing in common: none comes from the package itself. The cause is almost always an out-of-date list, an inexact name, or a forgotten sudo. Read the left column as the exact message displayed, and try the fix on the right before looking further.

Symptom	Likely cause	Fix
E: Unable to locate package	Package list out of date	sudo apt update then try again
No match for argument	Wrong package name	Check with dnf search keyword
E: Could not open lock file ... (13: Permission denied) (APT) or This command has to be run with superuser privileges (DNF)	Command run without sudo	Add sudo in front of the command
Removal takes away too many packages	Reverse dependencies	Answer n, check the dependencies
Package installed but command not found	The binary has another name	Look with dpkg -L name or rpm -ql name

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Key points

• Always apt update (or dnf check-update) before installing.
• apt install / dnf install handle dependencies automatically.
• apt search / dnf search find the right package name: search in English.
• apt remove keeps the configuration; apt purge deletes everything.
• Always read the summary before confirming an installation or a removal.
• Check with command --version that the installation worked.

Knowledge check

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