Ubuntu and Debian Package Management Tutorial04 Feb 2019
Package management is one of the components that contribute to the steep learning curve of using a linux system for a majority of first time linux users. Coming from the GUI environment of Windows or MacOS where installing/removing applications consist of clicking on Next -> Next -> I Agree -> Install/Uninstall, the terminal based package managers might be intimidating. And this issue is not constrained to first time users either. Even though I have used a linux system as my primary OS for several years now, I end up googling the errors and copy-pasting the answers from SO without the slightest idea of what I am doing most of the times. Hence, I am writing this blog post to be a glossary of the commands that we can use to fix our own package errors or to know what each command is doing even if we end up copy-pasting from the internet to fix our problems.
- Packaging format:
Debian and Ubuntu based distributions:
- Packaging format:
In this blog post, I will be covering the Debian/Ubuntu based distributions, since well, I am a Ubuntu user.
Debian/Ubuntu Package Management Tools
apt-getis used to interface with remote repositories. Main difference with
aptpulls from the remote repository into a local cache and then uses this copy in the cache.
apt-getuses the same methodology but refreshes the cache every time.
Like discussed earlier, this is the local cache that
Has both capabilities of the above tools. Can be dropped in place of both
The above tools are used to manage and pull packages from remote repositories.
dpkgoperates on the actual
.debfiles. It cannot resolve dependencies like
This is used for grouping of similarly related packages. For eg, if you want a MEAN stack setup, you can use
taskselto install all required packages instead of installing each of them individually.
sudo apt-get update
Updating the local cache with the latest info about the remote repositories.
sudo apt-get upgrade
Upgrade any component that do not require you to remove any other packages.
sudo apt-get dist-upgrade
Upgrade components when you are OK with removing/swapping other packages.
apt-cache search _package_
Search for package in the repositories. You will have to run
sudo apt-get updatebefore doing this.
sudo apt-get install _package_
sudo apt-get install _package1_ _package2_
sudo apt-get install _package=version_
Install a specific version of the package.
sudo dpkg-reconfigure _package_
Reconfigure package. Most of the packages, after you install them, they go through a configuration script that configures your system to use that particular package. Sometimes this include user prompts as well. If you want to do this configuration yourself after installation or rerun the configuration, use this command.
apt-get install -s _package_
Dry-run installation. Using this command you can see all the changes that installing package might do to your system without actually doing those changes. One important note is that this command does not require
sudoand hence can be used in systems where you do not have root privileges.
sudo dpkg --install _debfile.deb_
Install directly from the debfile.deb file. Note that this DOES NOT resolve dependencies.
sudo apt-get install -f
This command is used to fix dependency issues. While installing a package, if there are unmet dependencies, the installation will fail. If you’ve noticed,
apt-*commands resolve these dependencies automatically. Whereas using
.debfiles directly does not resolve dependencies. Hence, run this command in those scenarios.
sudo apt-get remove _package_
Remove the package without removing the configuration files. If you accidentally remove a package or install the same package after some time, you will need to save the configuration you did for your first installation.
sudo apt-get purge _package_
Remove the package and all it’s configuration files.
sudo apt-get autoremove
Remove any packages that were installed as dependencies and are no longer required. Use
--purgeto remove the configuration files of these packages.
sudo apt-get autoclean
Remove out-of-date packages in your system that are no longer maintained in the remote repository.
apt-cache show _package_
Show information about package.
dpkg --info _debfile.deb_
Show information about the debfile.deb file.
apt-cache depends _package_
Show dependencies of the package.
apt-cache rdepends _package_
Show packages that are dependent on this package (reverse dependency)
apt-cache policy _package_
If there are multiple versions of package installed, this command shows all the versions and the version being used as default.
Shows a list of every installed/partially-installed packages in the system. Each package is preceded by a series of characters.
- _u_: unknown - _i_: installed - _r_: removed - _p_: purged - _h_: version is held
- _n_: not installed - _i_: installed - _c_: configuration files are present, but the application is uninstalled - _u_: unpacked. The files are unpacked, but not configured yet - _f_: package is half installed, meaning that there was a failure part way through an installation that halted the operation - _w_: package is waiting for a trigger from a separate package - _p_: package has been triggered by another package
- _r_: re-installation is required. Package is broken.
dpkg -l _regex_
Search for all packages matching the regex.
dpkg -L _package_
List all files controlled by this package.
dpkg -S _/path/to/file_
This is the inverse of
-L, which gives a list of all files controlled by a package.
-Sprints the package that is controlling this file.
dpkg --get-selections > ~/packagelist.txt
Export the list of installed packages to
~/packagelist.txtfile which can be used to restore in a new system. This is analogous to
requirements.txtfile in python.
sudo add-apt-repository _ppa:owner_name/ppa_name_
This is used to add a PPA (Personal Package Archives). When you cannot find the required package in the default set of repositories and is available in another repository, we can add that PPA and install packages from there. This is specific to Ubuntu systems as of now. Before installing packages from the newly added repository, update the local cache with
sudo apt-get update. Usually PPAs have a smaller scope than a repository.
- Adding a new repository:
- Edit the
Create a new
/etc/apt/sources.list.d/new_repo.listfile (Must end with
Inside the file, add the new repository with the following format.
deb_or_deb-src url_of_repo release_code_name_or_suite component_names
- deb or deb-src: This identifies the type of repository. It can be either
deb(for conventional repositories) or
deb-src(for source repositories)
- url: URL of the repository.
- release_code_name or suite: Code name of your distribution’s release
- component_names: Labels for the source.
- Edit the
Exporting a package list:
If you want to setup a new system with all the packages from the old system, you first have to export the package details from the old system and install it in the new system.
dpkg --get-selections > ~/packagelist.txt: Export all package names
cp -R /etc/apt/sources.list* ~/sources: Backup your sources list.
apt-key exportall > ~/trusted_keys.txt: Backup your trusted keys
- Importing a package list:
sudo apt-key add ~/trusted_keys.txt
sudo cp -R ~sources/* /etc/apt/
sudo dpkg --clear-selections: Clear all non essential packages from the system for a clean slate.
sudo apt-get update
sudo apt-get install dselect: Install dselect tool
sudo dselect update
sudo dpkg --set-selections < packagelist.txt: Import from the package list.
sudo apt-get dselect-upgrade