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Return to Linux package managers, Arch Linux, Manjaro Linux or Package managers

The pacman package manager is one of the major distinguishing features of Arch Linux. It combines a simple binary package format with an easy-to-use build system. The goal of pacman is to make it possible to easily manage packages, whether they are from the official repositories or the user's own builds.

Pacman keeps the system up to date by synchronizing package lists with the master server. This server/client model also allows the user to download/install packages with a simple command, complete with all required dependencies.

Pacman is written in the C programming language and uses the (https://jlk.fjfi.cvut.cz/arch/manpages/man/bsdtar.1) tar format for packaging.

package contains tools such as makepkg and

. Other useful tools such as pactree and checkupdates are found in

(formerly part of pacman). Run

grep -E 'bin/.+'}} to see the full list.}}

What follows is just a small sample of the operations that pacman can perform. To read more examples, refer to

.

A package is an archive containing:

• all of the (compiled) files of an application
• metadata about the application, such as application name, version, dependencies, …
• installation files and directives for pacman
• (optionally) extra files to make your life easier, such as a start/stop script

Arch's package manager pacman can install, update, and remove those packages. Using packages instead of compiling and installing programs yourself has various benefits:

• easily updatable: pacman will update existing packages as soon as updates are available
• dependency checks: pacman handles dependencies for you, you only need to specify the program and pacman installs it together with every other program it needs
• clean removal: pacman has a list of every file in a package; this way, no files are unintentionally left behind when you decide to remove a package.

. Use the Querying package databases command to view the optional dependencies of a package.

• When installing a package which you require only as (optional) dependency of some other package (i.e. not required by you explicitly otherwise), it is recommended to use

  option. For details see the Installation reason section.}}

instead of

, as this could lead to dependency issues. See Partial upgrades are unsupported and BBS#89328.}}

To install a single package or list of packages, including dependencies, issue the following command:

# pacman -S ''package_name1'' ''package_name2'' ...

To install a list of packages with regex (see this forum thread):

# pacman -S $(pacman -Ssq ''package_regex'')

Sometimes there are multiple versions of a package in different repositories (e.g. extra and testing). To install the version from the extra repository in this example, the repository needs to be defined in front of the package name:

# pacman -S extra/''package_name''

To install a number of packages sharing similar patterns in their names one can use curly brace expansion. For example:

# pacman -S plasma-{desktop,mediacenter,nm}

This can be expanded to however many levels needed:

# pacman -S plasma-{workspace{,-wallpapers},pa}

A virtual package is a special package which does not exist by itself, but is provided by one or more other packages. Virtual packages allow other packages to not name a specific package as a dependency, in case there are several candidates. Virtual packages cannot be installed by their name, instead they become installed in your system when you have install a package providing the virtual package.

Some packages belong to a group of packages that can all be installed simultaneously. For example, issuing the command:

# pacman -S gnome

will prompt you to select the packages from the

group that you wish to install.

Sometimes a package group will contain a large amount of packages, and there may be only a few that you do or do not want to install. Instead of having to enter all the numbers except the ones you do not want, it is sometimes more convenient to select or exclude packages or ranges of packages with the following syntax:

Enter a selection (default=all): 1-10 15

which will select packages 1 through 10 and 15 for installation, or:

Enter a selection (default=all): ^5-8 ^2

which will select all packages except 5 through 8 and 2 for installation.

To see what packages belong to the gnome group, run:

# pacman -Sg gnome

Also visit https://www.archlinux.org/groups/ to see what package groups are available.

option.}}

To remove a single package, leaving all of its dependencies installed:

# pacman -R ''package_name''

To remove a package and its dependencies which are not required by any other installed package:

# pacman -Rs ''package_name''

The above may sometimes refuse to run when removing a group which contains otherwise needed packages. In this case try:

# pacman -Rsu ''package_name''

To remove a package, its dependencies and all the packages that depend on the target package:

# pacman -Rsc ''package_name''

To remove a package, which is required by another package, without removing the dependent package:

# pacman -Rdd ''package_name''

Pacman saves important configuration files when removing certain applications and names them with the extension: .pacsave. To prevent the creation of these backup files use the

option:

# pacman -Rn ''package_name''

Pacman can update all packages on the system with just one command. This could take quite a while depending on how up-to-date the system is. The following command synchronizes the repository databases and updates the system's packages, excluding “local” packages that are not in the configured repositories:

# pacman -Syu

Pacman queries the local package database with the

flag, the sync database with the

flag and the files database with the

flag. See

,

and

for the respective suboptions of each flag.

Pacman can search for packages in the database, searching both in packages' names and descriptions:

$ pacman -Ss ''string1'' ''string2'' ...

Sometimes,

's builtin ERE (Extended Regular Expressions) can cause a lot of unwanted results, so it has to be limited to match the package name only; not the description nor any other field:

$ pacman -Ss '^vim-'

To search for already installed packages:

$ pacman -Qs ''string1'' ''string2'' ...

To search for package file names in remote packages:

$ pacman -F ''string1'' ''string2'' ...

To display extensive information about a given package:

$ pacman -Si ''package_name''

For locally installed packages:

$ pacman -Qi ''package_name''

Passing two

flags will also display the list of backup files and their modification states:

$ pacman -Qii ''package_name''

To retrieve a list of the files installed by a package:

$ pacman -Ql ''package_name''

To retrieve a list of the files installed by a remote package:

$ pacman -Fl ''package_name''

To verify the presence of the files installed by a package:

$ pacman -Qk ''package_name''

Passing the

flag twice will perform a more thorough check.

To query the database to know which package a file in the file system belongs to:

$ pacman -Qo ''/path/to/file_name''

To query the database to know which remote package a file belongs to:

$ pacman -F ''/path/to/file_name''

To list all packages no longer required as dependencies (orphans):

$ pacman -Qdt

in your hook:

}}

To list all packages explicitly installed and not required as dependencies:

$ pacman -Qet

See Pacman/Tips and tricks for more examples.

is not part of the

package anymore. Instead it can be found in

.}}

To view the dependency tree of a package:

$ pactree ''package_name''

To view the dependant tree of a package, pass the reverse flag

to pactree, or use whoneeds from

.

The pacman databases are normally located at

. For each repository specified in

there will be a corresponding database file located there. Database files are gzipped tar archives containing one directory for each package, for example for the

package:

– desc }}

The

file contains meta data such as the package description, dependencies, file size and MD5 hash.

Pacman stores its downloaded packages in

and does not remove the old or uninstalled versions automatically. This has some advantages:

1. It allows to downgrade a package without the need to retrieve the previous version through other means, such as the Arch Linux Archive.
2. A package that has been uninstalled can easily be reinstalled directly from the cache folder, not requiring a new download from the repository.

However, it is necessary to deliberately clean up the cache periodically to prevent the folder to grow indefinitely in size.

The

script, provided within the

package, deletes all cached versions of installed and uninstalled packages, except for the most recent 3, by default:

# paccache -r

Enable and start

to discard unused packages weekly.

.}}

You can also define how many recent versions you want to keep. To retain only one past version use:

# paccache -rk1

Add the

/

switch to limit the action of paccache to uninstalled packages. For example to remove all cached versions of uninstalled packages, use the following:

# paccache -ruk0

See

for more options.

Pacman also has some built-in options to clean the cache and the leftover database files from repositories which are no longer listed in the configuration file

. However pacman does not offer the possibility to keep a number of past versions and is therefore more aggressive than paccache default options.

To remove all the cached packages that are not currently installed, and the unused sync database, execute:

# pacman -Sc

To remove all files from the cache, use the clean switch twice, this is the most aggressive approach and will leave nothing in the cache folder:

# pacman -Scc

and

are two further alternatives to clean the cache.

Download a package without installing it:

# pacman -Sw ''package_name''

Install a 'local' package that is not from a remote repository (e.g. the package is from the AUR):

# pacman -U ''/path/to/package/package_name-version.pkg.tar.xz''

To keep a copy of the local package in pacmans cache, use:

# pacman -U file:///''path/to/package/package_name-version.pkg.tar.xz''

Install a 'remote' package (not from a repository stated in pacmans configuration files):

# pacman -U ''http://www.example.com/repo/example.pkg.tar.xz''

To inhibit the

,

and

actions,

can be used.

Pacman always lists packages to be installed or removed and asks for permission before it takes action.

The pacman database distinguishes the installed packages in two groups according to the reason why they were installed:

• explicitly-installed: the packages that were literally passed to a generic pacman

  or

  command;

• dependencies: the packages that, despite never (in general) having been passed to a pacman installation command, were implicitly installed because required by another package that was explicitly installed.

When installing a package, it is possible to force its installation reason to dependency with:

# pacman -S --asdeps ''package_name''

will cause it such that if you remove orphans, pacman will also remove leftover optional dependencies.}}

When reinstalling a package, though, the current installation reason is preserved by default.

The list of explicitly-installed packages can be shown with

, while the complementary list of dependencies can be shown with

.

To change the installation reason of an already installed package, execute:

# pacman -D --asdeps ''package_name''

Use

to do the opposite operation.

and

options when upgrading, such as with

, is discouraged. This would change the installation reason of not only the package being installed, but also the packages being upgraded.}}

Sync the files database:

# pacman -Fy

Search for a package containing a file, e.g.:

For advanced functionality install pkgfile, which uses a separate database with all files and their associated packages.

Pacmans settings are located in

Most likely the initramfs became corrupted during a kernel update (improper use of pacmans

option can be a cause). There are two options; first, try the Fallback entry.

key when the boot loader menu shows up (for Syslinux) or

(for GRUB or systemd-boot), rename it

and press

or

(depending on your boot loader) to boot with the new parameters.}}

Once the system starts, run this command (for the stock

kernel) either from the console or from a terminal to rebuild the initramfs image:

# mkinitcpio -p linux

If that does not work, from a current Arch release (CD/DVD or USB stick), mount your root and boot partitions. Then chroot using arch-chroot:

# arch-chroot /mnt
# pacman -Syu mkinitcpio systemd linux

script.

• If pacman fails with

  , please check your internet connection.

• If you cannot enter the arch-chroot or chroot environment but need to re-install packages you can use the command

  to use pacman on your root partition.}}

Reinstalling the kernel (the

package) will automatically re-generate the initramfs image with

. There is no need to do this separately.

Afterwards, it is recommended that you run

,

and

.

Potential solutions:

• Update the known keys, i.e.
• Manually upgrade

  package first, i.e.

• Follow Resetting all the keys

If installing Arch with an outdated ISO, you are likely prompted to import PGP keys. Agree to download the key to proceed. If you are unable to add the PGP key successfully, update the keyring or upgrade

(see above).

If packages are signed with new keys, which were only recently added to

, these keys are not locally available during update (chicken-egg-problem). The installed

does not contain the key, until it is updated. Pacman tries to bypass this by a lookup through a key-server, which might not be possible e.g. behind proxys or firewalls and results in the stated error. Upgrade

first as shown above.

When the system time is faulty, signing keys are considered expired (or invalid) and signature checks on packages will fail with the following error:

error: ''package'': signature from "User " is invalid
error: failed to commit transaction (invalid or corrupted package (PGP signature))
Errors occured, no packages were upgraded.

Make sure to correct the system time, for example with

run as root, and run

as root before subsequent installations or upgrades.

As the error message says, your locale is not correctly configured. See Locale.

Make sure that the relevant environment variables (

,

etc.) are set up. If you use pacman with sudo, you need to configure sudo to pass these environment variables to pacman. Also, ensure the configuration of dirmngr has

in

to honor the proxy when refreshing the keys.

To reinstall all the native packages:

pacman -S -}} or

(the

option preserves the installation reason by default).

You will then need to reinstall all the foreign packages, which can be listed with

.

It looks like previous pacman transaction removed or corrupted shared libraries needed for pacman itself.

To recover from this situation you need to unpack required libraries to your filesystem manually. First find what package contains the missed library and then locate it in the pacman cache (

). Unpack required shared library to the filesystem. This will allow to run pacman.

Now you need to reinstall the broken package. Note that you need to use

flag as you just unpacked system files and pacman does not know about it. Pacman will correctly replace our shared library file with one from package.

That's it. Update the rest of the system.

Some issues have been reported regarding network problems that prevent pacman from updating/synchronizing repositories. s://bbs.archlinux.org/viewtopic.php?id=68944 s://bbs.archlinux.org/viewtopic.php?id=65728 When installing Arch Linux natively, these issues have been resolved by replacing the default pacman file downloader with an alternative (see Improve pacman performance for more details). When installing Arch Linux as a guest OS in VirtualBox, this issue has also been addressed by using Host interface instead of NAT in the machine properties.

If you receive this error message with correct mirrors, try setting a different name server.

If you want to install a package on an sshfs mount using

and receive this error, move the package to a local directory and try to install again.

When successfully completing a package transaction, pacman performs the following high-level steps:

1. pacman obtains the to-be installed package file for all packages queued in a transaction.
2. pacman performs various checks that the packages can likely be installed.
3. If pre-existing pacman

   hooks apply, they are executed.

4. Each package is installed/upgraded/removed in turn.
   1. If the package has an install script, its

      function is executed (or

      or

      in the case of an upgraded or removed package).

   2. pacman deletes all the files from a pre-existing version of the package (in the case of an upgraded or removed package). However, files that were marked as configuration files in the package are kept (see Pacman/Pacnew and Pacsave).
   3. pacman untars the package and dumps its files into the file system (in the case of an installed or upgraded package). Files that would overwrite kept, and manually modified, configuration files (see previous step), are stored with a new name (.pacnew).
   4. If the package has an install script, its

      function is executed (or

      or

      in the case of an upgraded or removed package).

5. If pacman

   hooks that exist at the end of the transaction apply, they are executed.

• Pacman Home Page