pacman tips
Related articles
This is a collection of common tips for new pacman users.
Contents
- 1 Cosmetic and convenience
-
2 Maintenance
- 2.1 Listing latest installed packages
- 2.2 Listing installed packages with size
- 2.3 Listing files owned by a package with size
- 2.4 Listing installed packages with version
- 2.5 List available updates
- 2.6 Identify files not owned by any package
- 2.7 Removing orphaned packages
- 2.8 Removing unused packages
- 2.9 Removing everything but base group
- 2.10 Listing official installed packages only
- 2.11 Getting the dependencies list of several packages
- 2.12 Getting the size of several packages
- 2.13 Listing changed configuration files
- 2.14 Listing all packages that nothing else depends on
- 2.15 Backing up Local database with systemd
-
3 Installation and recovery
- 3.1 Installing packages from a CD/DVD or USB stick
- 3.2 Custom local repository
- 3.3 Network shared pacman cache
- 3.4 Recreate a package from the file system
- 3.5 Backing up and retrieving a list of installed packages
- 3.6 List installed packages that are not in a specified group or repository
- 3.7 Listing all changed files from packages
- 3.8 Reinstalling all packages
- 3.9 Restore pacman's local database
- 3.10 Recovering a USB key from existing install
- 3.11 Extracting contents of a .pkg file
- 3.12 Viewing a single file inside a .pkg file
- 3.13 Find applications that use libraries from older packages
Cosmetic and convenience
Color output
Pacman has a color option. Uncomment the "Color" line in /etc/pacman.conf
.
Shortcuts
The following instructions allow users to run some of the more common pacman commands without the need to type them fully via a script alias.
Configure the shell
Add the following examples to your shell configuration script (they work at least in Bash and Zsh), then source it.
# Pacman alias examples alias pacupg="sudo pacman -Syu" # Synchronize with repositories and then upgrade packages that are out of date on the local system. alias pacdl="pacman -Sw" # Download specified package(s) as .tar.xz ball alias pacin="sudo pacman -S" # Install specific package(s) from the repositories alias pacins="sudo pacman -U" # Install specific package not from the repositories but from a file alias pacre="sudo pacman -R" # Remove the specified package(s), retaining its configuration(s) and required dependencies alias pacrem="sudo pacman -Rns" # Remove the specified package(s), its configuration(s) and unneeded dependencies alias pacrep="pacman -Si" # Display information about a given package in the repositories alias pacreps="pacman -Ss" # Search for package(s) in the repositories alias pacloc="pacman -Qi" # Display information about a given package in the local database alias paclocs="pacman -Qs" # Search for package(s) in the local database alias paclo="pacman -Qdt" # List all packages which are orphaned alias pacc="sudo pacman -Scc" # Clean cache - delete all the package files in the cache alias paclf="pacman -Ql" # List all files installed by a given package alias pacown="pacman -Qo" # Show package(s) owning the specified file(s) alias pacexpl="pacman -D --asexp" # Mark one or more installed packages as explicitly installed alias pacimpl="pacman -D --asdep" # Mark one or more installed packages as non explicitly installed # Additional pacman alias examples alias pacupd="sudo pacman -Sy && sudo abs" # Update and refresh the local package and ABS databases against repositories alias pacinsd="sudo pacman -S --asdeps" # Install given package(s) as dependencies alias pacmir="sudo pacman -Syy" # Force refresh of all package lists after updating /etc/pacman.d/mirrorlist
The following commands could be useful, but also dangerous. Please, know perfectly what are you doing when you use them:
# dealing with the following message from pacman: # # error: couldnt lock database: file exists # if you are sure a package manager is not already running, you can remove /var/lib/pacman/db.lck alias pacunlock="sudo rm /var/lib/pacman/db.lck" # Delete the lock file /var/lib/pacman/db.lck alias paclock="sudo touch /var/lib/pacman/db.lck" # Create the lock file /var/lib/pacman/db.lck
Usage
Perform the respective commands by simply typing the alias name. For example, to synchronize with repositories and then upgrade packages that are out of date on the local system:
$ pacupg
Install packages from repositories:
$ pacin <package1> <package2> <package3>
Install a custom built package:
$ pacins /path/to/<package>
Completely remove a locally installed package:
$ pacrem <package>
Search for available packages in the repositories:
$ pacreps <keywords>
Display information about a package (e.g. size, dependencies) in the repositories:
$ pacrep <keywords>
Notes
The aliases used above are merely examples. By following the syntax samples above, rename the aliases as convenient. For example:
alias pacrem='sudo pacman -Rns' alias pacout='sudo pacman -Rns'
In the case above, the commands pacrem
and pacout
both call your shell to execute the same command.
Operations and Bash syntax
In addition to pacman's standard set of features, there are ways to extend its usability through rudimentary Bash commands/syntax.
- To install a number of packages sharing similar patterns in their names -- not the entire group nor all matching packages; eg. kde:
# pacman -S kde-{applets,theme,tools}
- Of course, that is not limited and can be expanded to however many levels needed:
# pacman -S kde-{ui-{kde,kdemod},kdeartwork}
- Sometimes,
-s
's builtin ERE 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-'
- pacman has the
-q
operand to hide the version column, so it is possible to query and reinstall packages with "compiz" as part of their name:
# pacman -S $(pacman -Qq | grep compiz)
- Or install all packages available in a repository (kde-unstable for example):
# pacman -S $(pacman -Slq kde-unstable)
Maintenance
House keeping, in the interest of keeping a clean system and following The Arch Way.
See also System maintenance.
Listing latest installed packages
Install expac and run expac --timefmt='%Y-%m-%d %T' '%l\t%n' | sort | tail -20
or expac --timefmt=%s '%l\t%n' | sort -n | tail -20
Listing installed packages with size
You may want to get the list of installed packages sorted by size, which may be useful when freeing space on your hard drive.
- Install expac and run
expac -s "%-30n %m" | sort -hk 2 | awk '{printf "%s %.0f MiB\n", $1, $2/1024/1024}' | column -t
- Invoke pacgraph with the -c option to produce a list of all installed packages with their respective sizes on the system. pacgraph is available from [community].
- List explicitly installed packages not in base or base-devel with size and description:
expac -HM "%011m\t%-20n\t%10d" $( comm -23 <(pacman -Qqen|sort) <(pacman -Qqg base base-devel|sort) ) | sort -n
Listing files owned by a package with size
This one might come in handy if you have found that a specific package uses a huge amount of space and you want to find out which files make up the most of that.
$ pacman -Qlq package | grep -v '/$' | xargs du -h | sort -h
Listing installed packages with version
You may want to get the list of installed packages with their version, which is useful when reporting bugs or discussing installed packages.
- List all explicitly installed packages:
pacman -Qe
. - List all foreign packages (typically manually downloaded and installed):
pacman -Qm
. - List all native packages (installed from the sync database(s)):
pacman -Qn
. - List packages by regex:
pacman -Qs <regex> | awk 'BEGIN { RS="\n" ; FS="/" } { print $2 }' | awk '{ if(NF > 0) print $1, $2 }'
- Install expac and run
expac -s "%-30n %v"
List available updates
Pacman comes with a script, checkupdates
, which does not require root permissions.
Identify files not owned by any package
Periodic checks for files outside of pacman database are recommended. These files are often some 3rd party applications installed using the usual procedure (e.g. ./configure && make && make install
). Search the file-system for these files (or symlinks) using this simple script:
pacman-disowned
#!/bin/sh tmp=${TMPDIR-/tmp}/pacman-disowned-$UID-$$ db=$tmp/db fs=$tmp/fs mkdir "$tmp" trap 'rm -rf "$tmp"' EXIT pacman -Qlq | sort -u > "$db" find /etc /opt /usr ! -name lost+found \( -type d -printf '%p/\n' -o -print \) | sort > "$fs" comm -23 "$fs" "$db"
To generate the list:
$ pacman-disowned > non-db.txt
Note that one should not delete all files listed in non-db.txt
without confirming each entry. There could be various configuration files, logs, etc., so use this list responsibly and only proceed after extensively searching for cross-references using grep
.
Here are some one-liner scripts that will be helpful.
Show dirs that do not belong to any package:
alias pacman-disowned-dirs="comm -23 <(sudo find / \( -path '/dev' -o -path '/sys' -o -path '/run' -o -path '/tmp' -o -path '/mnt' -o -path '/srv' -o -path '/proc' -o -path '/boot' -o -path '/home' -o -path '/root' -o -path '/media' -o -path '/var/lib/pacman' -o -path '/var/cache/pacman' \) -prune -o -type d -print | sed 's/\([^/]\)$/\1\//' | sort -u) <(pacman -Qlq | sort -u)"
Show files that do not belong to any package:
alias pacman-disowned-files="comm -23 <(sudo find / \( -path '/dev' -o -path '/sys' -o -path '/run' -o -path '/tmp' -o -path '/mnt' -o -path '/srv' -o -path '/proc' -o -path '/boot' -o -path '/home' -o -path '/root' -o -path '/media' -o -path '/var/lib/pacman' -o -path '/var/cache/pacman' \) -prune -o -type f -print | sort -u) <(pacman -Qlq | sort -u)"
The script in the lostfilesAUR package also excludes common user-created configuration files and directories created by software at runtime.
Removing orphaned packages
For recursively removing orphans and their configuration files:
# pacman -Rns $(pacman -Qtdq)
If no orphans were found, pacman errors with error: no targets specified
. This is expected as no arguments were passed to pacman -Rns
.
The following function is easily inserted into ~/.bashrc
and removes orphans, if found:
~/.bashrc
orphans() { if [[ ! -n $(pacman -Qdt) ]]; then echo "No orphans to remove." else sudo pacman -Rns $(pacman -Qdtq) fi }
Removing unused packages
Because a lighter system is easier to maintain, occasionally looking through explicitly installed packages and manually selecting unused packages to be removed can be helpful.
To list explicitly installed packages available in the official repositories:
$ pacman -Qen
To list explicitly installed packages not available in official repositories:
$ pacman -Qem
Removing everything but base group
If it is ever necessary to remove all packages except the base group, try this one liner:
# pacman -R $(comm -23 <(pacman -Qq|sort) <((for i in $(pacman -Qqg base); do pactree -ul $i; done)|sort -u|cut -d ' ' -f 1))
The one-liner was originally devised in this discussion, and later improved in this article.
Notes:
-
comm
requires sorted input otherwise you get e.g.comm: file 1 is not in sorted order
. -
pactree
prints the package name followed by what it provides. For example:
$ pactree -lu logrotate
logrotate popt glibc linux-api-headers tzdata dcron cron bash readline ncurses gzip
The dcron cron
line seems to cause problems, that is why cut -d ' ' -f 1
is needed - to keep just the package name.
Listing official installed packages only
$ pacman -Qqn
This list packages that are found in the sync database(s). If the user has unofficial repositories configured, it will list packages from such repositories too.
Getting the dependencies list of several packages
Dependencies are alphabetically sorted and doubles are removed.
Note that you can use pacman -Qi
to improve response time a little. But
you will not be able to query as many packages. Unfound packages are simply skipped
(hence the 2>/dev/null
).
You can get dependencies of AUR packages as well if you use yaourt -Si
,
but it will slow down the queries.
$ pacman -Si $@ 2>/dev/null | awk -F ": " -v filter="^Depends" \ '$0 ~ filter {gsub(/[>=<][^ ]*/,"",$2) ; gsub(/ +/,"\n",$2) ; print $2}' | sort -u
Alternatively, you can use expac
: expac -l '\n' %E -S $@ | sort -u
.
Getting the size of several packages
You can use (and tweak) this little shell function:
~/.bashrc
pacman-size() { CMD="pacman -Si" SEP=": " TOTAL_SIZE=0 RESULT=$(eval "${CMD} $@ 2>/dev/null" | awk -F "$SEP" -v filter="Size" -v pkg="^Name" \ '$0 ~ pkg {pkgname=$2} $0 ~ filter {gsub(/\..*/,"") ; printf("%6s KiB %s\n", $2, pkgname)}' | sort -u -k3) echo "$RESULT" ## Print total size. echo "$RESULT" | awk '{TOTAL=$1+TOTAL} END {printf("Total : %d KiB\n",TOTAL)}' }
As told for the dependencies list, you can use pacman -Qi
instead, but
not yaourt since AUR's PKGBUILD do not have size information.
A nice one-liner:
$ pacman -Si "$@" 2>/dev/null | awk -F ": " -v filter="Size" -v pkg="Name" '$0 ~ pkg {pkgname=$2} $0 ~ filter {gsub(/\..*/,"") ; printf("%6s KiB %s\n", $2, pkgname)}' | sort -u -k3 | tee >(awk '{TOTAL=$1+TOTAL} END {printf("Total : %d KiB\n",TOTAL)}')
You should replace "$@" with packages, or put this line in a shell function.
Listing changed configuration files
If you want to backup your system configuration files you could copy all files in /etc/
, but usually you are only interested in the files that you have changed. In this case you want to list those changed configuration files, we can do this with the following command:
# pacman -Qii | awk '/^MODIFIED/ {print $2}'
The following script does the same. You need to run it as root or with sudo.
changed-files.sh
#!/bin/bash for package in /var/lib/pacman/local/*; do sed '/^%BACKUP%$/,/^%/!d' $package/files | tail -n+2 | grep -v '^$' | while read file hash; do [ "$(md5sum /$file | (read hash file; echo $hash))" != "$hash" ] && echo $(basename $package) /$file done done
Listing all packages that nothing else depends on
If you want to generate a list of all installed packages that nothing else depends on, you can use the following script. This is very helpful if you are trying to free hard drive space and have installed a lot of packages that you may not remember. You can browse through the output to find packages which you no longer need.
clean
#!/bin/bash # This script is designed to help you clean your computer from unneeded # packages. The script will find all packages that no other installed package # depends on. It will output this list of packages excluding any you have # placed in the ignore list. You may browse through the script's output and # remove any packages you do not need. # Enter groups and packages here which you know you wish to keep. They will # not be included in the list of unrequired packages later. ignoregrp="base base-devel" ignorepkg="" comm -23 <(pacman -Qqt | sort) <(echo $ignorepkg | tr ' ' '\n' | cat <(pacman -Sqg $ignoregrp) - | sort -u)
For list with descriptions for packages:
expac -HM "%-20n\t%10d" $( comm -23 <(pacman -Qqt|sort) <(pacman -Qqg base base-devel|sort) )
Backing up Local database with systemd
systemd can take snapshots of the pacman local database, each time it is modified.
Use the following scripts, changing the value of $pakbak
for the backup location accordingly. The pakbak.service
can also automaticall be enabled on boot:
/usr/lib/systemd/scripts/pakbak_script
#!/bin/bash declare -r pakbak="/pakbak.tar.xz"; ## set backup location tar -cJf "$pakbak" "/var/lib/pacman/local"; ## compress & store pacman local database in $pakbak
/usr/lib/systemd/system/pakbak.service
[Unit] Description=Back up pacman database [Service] Type=oneshot ExecStart=/bin/bash /usr/lib/systemd/scripts/pakbak_script RemainAfterExit=no
/usr/lib/systemd/system/pakbak.path
[Unit] Description=Back up pacman database [Path] PathChanged=/var/lib/pacman/local Unit=pakbak.service [Install] WantedBy=multi-user.target
Installation and recovery
Alternative ways of getting and restoring packages.
Installing packages from a CD/DVD or USB stick
To download packages, or groups of packages:
# cd ~/Packages # pacman -Syw base base-devel grub-bios xorg gimp --cachedir . # repo-add ./custom.db.tar.gz ./*
Then you can burn the "Packages" folder to a CD/DVD or transfer it to a USB stick, external HDD, etc.
To install:
1. Mount the media:
# mkdir /mnt/repo # mount /dev/sr0 /mnt/repo #For a CD/DVD. # mount /dev/sdxY /mnt/repo #For a USB stick.
2. Edit pacman.conf
and add this repository before the other ones (e.g. extra, core, etc.). This is important. Do not just uncomment the one on the bottom. This way it ensures that the files from the CD/DVD/USB take precedence over those in the standard repositories:
/etc/pacman.conf
[custom] SigLevel = PackageRequired Server = file:///mnt/repo/Packages
3. Finally, synchronize the pacman database to be able to use the new repository:
# pacman -Sy
Custom local repository
Use the repo-add script included with Pacman to generate a database for a personal repository. Use repo-add --help
for more details on its usage. Simply store all of the built packages to be included in the repository in one directory, and execute the following command (where repo is the name of the custom repository):
$ repo-add /path/to/repo.db.tar.gz /path/to/*.pkg.tar.xz
To add a new package to the database, or to replace the old version of an existing package in the database, run:
$ repo-add /path/to/repo.db.tar.gz /path/to/packagetoadd-1.0-1-i686.pkg.tar.xz
repo-remove is used in the exact same manner as repo-add, except that the packages listed on the command line are removed from the repository database.
Once the local repository database has been created, add the repository to pacman.conf
for each system that is to use the repository. An example of a custom repository is in pacman.conf
. The repository's name is the database filename with the file extension omitted. In the case of the example above the repository's name would simply be repo. Reference the repository's location using a file://
url, or via FTP using ftp://localhost/path/to/directory.
If willing, add the custom repository to the list of unofficial user repositories, so that the community can benefit from it.
Read-only cache
If you are looking for a quick and dirty solution, you can simply run a standalone webserver which other computers can use as a first mirror: darkhttpd /var/cache/pacman/pkg
. Just add this server at the top of your mirror list. Be aware that you might get a lot of 404 errors, due to cache misses, depending on what you do, but pacman will try the next (real) mirrors when that happens.
Read-write cache
In order to share packages between multiple computers, simply share /var/cache/pacman/
using any network-based mount protocol. This section shows how to use shfs or sshfs to share a package cache plus the related library-directories between multiple computers on the same local network. Keep in mind that a network shared cache can be slow depending on the file-system choice, among other factors.
First, install any network-supporting filesystem; for example sshfs, shfs, ftpfs, smbfs or nfs.
Then, to share the actual packages, mount /var/cache/pacman/pkg
from the server to /var/cache/pacman/pkg
on every client machine.
Synchronize pacman package cache using BitTorrent Sync
BitTorrent Sync is a new way of synchronizing folder via network (it works in LAN and over the internet). It is peer-to-peer so you do not need to set up a server: follow the link for more information. How to share a pacman cache using BitTorrent Sync:
- First install the btsyncAUR package from the AUR on the machines you want to sync
- Follow the installation instructions of the AUR package or on the BitTorrent Sync wiki page
- set up BitTorrent Sync to work for the root account. This process requires read/write to the pacman package cache.
- make sure to set a good password on btsync's web UI
- start the systemd daemon for btsync.
- in the btsync Web GUI add a new synchronized folder on the first machine and generate a new Secret. Point the folder to
/var/cache/pacman/pkg
- Add the folder on all the other machines using the same Secret to share the cached packages between all systems. Or, to set the first system as a master and the others as slaves, use the Read Only Secret. Be sure to point it to
/var/cache/pacman/pkg
Now the machines should connect and start synchronizing their cache. Pacman works as expected even during synchronization. The process of syncing is entirely automatic.
Preventing unwanted cache purges
By default, pacman -Sc
removes package tarballs from the cache that correspond to packages that are not installed on the machine the command was issued on. Because pacman cannot predict what packages are installed on all machines that share the cache, it will end up deleting files that should not be.
To clean up the cache so that only outdated tarballs are deleted, add this entry in the [options]
section of /etc/pacman.conf
:
CleanMethod = KeepCurrent
Recreate a package from the file system
To recreate a package from the file system, use bacman (included with pacman). Files from the system are taken as they are, hence any modifications will be present in the assembled package. Distributing the recreated package is therefore discouraged; see ABS and Arch Rollback Machine for alternatives.
An alternative tool would be fakepkgAUR. It supports parallelization through parallel and can handle multiple input packages in one command, which bacman both does not support.
Backing up and retrieving a list of installed packages
It is good practice to keep periodic backups of all pacman-installed packages. In the event of a system crash which is unrecoverable by other means, pacman can then easily reinstall the very same packages onto a new installation.
- First, backup the current list of non-local packages:
$ pacman -Qqen > pkglist.txt
- Store the
pkglist.txt
on a USB key or other convenient medium or gist.github.com or Evernote, Dropbox, etc.
- Copy the
pkglist.txt
file to the new installation, and navigate to the directory containing it.
- Issue the following command to install from the backup list:
# pacman -S $(< pkglist.txt)
In the case you have a list which was not generated like mentioned above, there may be foreign packages in it (i.e. packages not belonging to any repos you have configured, or packages from the AUR).
In such a case, you may still want to install all available packages from that list:
# pacman -S --needed $(comm -12 <(pacman -Slq|sort) <(sort badpkdlist) )
Explanation:
-
pacman -Slq
lists all available softwares, but the list is sorted by repository first, hence thesort
command. - Sorted files are required in order to make the
comm
command work. - The
-12
parameter display lines common to both entries. - The
--needed
switch is used to skip already installed packages.
You may also try to install all unavailable packages (those not in the repos) from the AUR using yaourt (not recommended unless you know exactly what you are doing):
$ yaourt -S --needed $(comm -13 <(pacman -Slq|sort) <(sort badpkdlist) )
Finally, you may want to remove all the packages on your system that are not mentioned in the list.
# pacman -Rsu $(comm -23 <(pacman -Qq|sort) <(sort pkglist))
List installed packages that are not in a specified group or repository
The following command will list any installed packages that are not in either base or base-devel, and as such were likely installed manually by the user:
$ comm -23 <(pacman -Qeq | sort) <(pacman -Qgq base base-devel | sort)
List all installed packages that are not in specified repository (repo_name
in example):
$ comm -23 <(pacman -Qtq | sort) <(pacman -Slq repo_name | sort)
List all installed packages that are in the repo_name
repository:
$ comm -12 <(pacman -Qtq | sort) <(pacman -Slq repo_name | sort)
Listing all changed files from packages
If you are suspecting file corruption (e.g. by software / hardware failure), but don't know for sure whether / which files really got corrupted, you might want to compare with the hash sums in the packages. This can be done with the following script.
The script depends on the accuracy of pacman's database in /var/lib/pacman/local/
and the used programs such as bash, grep and so on. For recovery of the database see #Restore pacman's local database. The mtree
files can also be extracted as .MTREE
from the respective package files.
#!/bin/bash -e # Select the hash algorithm. Currently available (see mtree files and mtree(5)): # md5, sha256 algo="md5" for package in /var/lib/pacman/local/*; do [ "$package" = "/var/lib/pacman/local/ALPM_DB_VERSION" ] && continue # get files and hash sums zgrep " ${algo}digest=" "$package/mtree" | grep -Ev '^\./\.[A-Z]+' | \ sed 's/^\([^ ]*\).*'"${algo}"'digest=\([a-f0-9]*\).*/\1 \2/' | \ while read -r file hash do # expand "\nnn" (in mtree) / "\0nnn" (for echo) escapes of ASCII # characters (octal representation) for ascii in $(grep -Eo '\\[0-9]{1,3}' <<< "$file"); do file="$(sed "s/\\$ascii/$(echo -e "\0${ascii:1}")/" <<< "$file")" done # check file hash if [ "$("${algo}sum" /"$file" | awk '{ print $1; }')" != "$hash" ]; then echo "$(basename "$package")" /"$file" fi done done
Reinstalling all packages
To reinstall all native packages, use:
# pacman -Qenq | pacman -S -
Foreign (AUR) packages must be reinstalled separately; you can list them with pacman -Qemq
.
Pacman preserves the installation reason by default.
Restore pacman's local database
Signs that pacman needs a local database restoration:
-
pacman -Q
gives absolutely no output, andpacman -Syu
erroneously reports that the system is up to date. - When trying to install a package using
pacman -S package
, and it outputs a list of already satisfied dependencies. - When
testdb
(part of pacman) reports database inconsistency.
Most likely, pacman's database of installed software, /var/lib/pacman/local
, has been corrupted or deleted. While this is a serious problem, it can be restored by following the instructions below.
Firstly, make sure pacman's log file is present:
$ ls /var/log/pacman.log
If it does not exist, it is not possible to continue with this method. You may be able to use Xyne's package detection script to recreate the database. If not, then the likely solution is to re-install the entire system.
Log filter script
pacrecover
#!/bin/bash -e . /etc/makepkg.conf PKGCACHE=$((grep -m 1 '^CacheDir' /etc/pacman.conf || echo 'CacheDir = /var/cache/pacman/pkg') | sed 's/CacheDir = //') pkgdirs=("$@" "$PKGDEST" "$PKGCACHE") while read -r -a parampart; do pkgname="${parampart[0]}-${parampart[1]}-*.pkg.tar.xz" for pkgdir in ${pkgdirs[@]}; do pkgpath="$pkgdir"/$pkgname [ -f $pkgpath ] && { echo $pkgpath; break; }; done || echo ${parampart[0]} 1>&2 done
Make the script executable:
$ chmod +x pacrecover
Generating the package recovery list
Run the script (optionally passing additional directories with packages as parameters):
$ paclog-pkglist /var/log/pacman.log | ./pacrecover >files.list 2>pkglist.orig
This way two files will be created: files.list
with package files, still present on machine and pkglist.orig
, packages from which should be downloaded. Later operation may result in mismatch between files of older versions of package, still present on machine, and files, found in new version. Such mismatches will have to be fixed manually.
Here is a way to automatically restrict second list to packages available in a repository:
$ { cat pkglist.orig; pacman -Slq; } | sort | uniq -d > pkglist
Check if some important base package are missing, and add them to the list:
$ comm -23 <(pacman -Sgq base) pkglist.orig >> pkglist
Proceed once the contents of both lists are satisfactory, since they will be used to restore pacman's installed package database; /var/lib/pacman/local/
.
Performing the recovery
Define bash alias for recovery purposes:
# recovery-pacman() { pacman "$@" \ --log /dev/null \ --noscriptlet \ --dbonly \ --force \ --nodeps \ --needed \ # }
--log /dev/null
allows to avoid needless pollution of pacman log, --needed
will save some time by skipping packages, already present in database, --nodeps
will allow installation of cached packages, even if packages being installed depend on newer versions. Rest of options will allow pacman to operate without reading/writing filesystem.
Populate the sync database:
# pacman -Sy
Start database generation by installing locally available package files from files.list
:
# recovery-pacman -U $(< files.list)
Install the rest from pkglist
:
# recovery-pacman -S $(< pkglist)
Update the local database so that packages that are not required by any other package are marked as explicitly installed and the other as dependences. You will need be extra careful in the future when removing packages, but with the original database lost is the best we can do.
# pacman -D --asdeps $(pacman -Qq) # pacman -D --asexplicit $(pacman -Qtq)
Optionally check all installed packages for corruption:
# pacman -Qk
Optionally #Identify files not owned by any package.
Update all packages:
# pacman -Su
Recovering a USB key from existing install
If you have Arch installed on a USB key and manage to mess it up (e.g. removing it while it is still being written to), then it is possible to re-install all the packages and hopefully get it back up and working again (assuming USB key is mounted in /newarch)
# pacman -S $(pacman -Qq --dbpath /newarch/var/lib/pacman) --root /newarch --dbpath /newarch/var/lib/pacman
Extracting contents of a .pkg file
The .pkg
files ending in .xz
are simply tar'ed archives that can be decompressed with:
$ tar xvf package.tar.xz
If you want to extract a couple of files out of a .pkg
file, this would be a way to do it.
Viewing a single file inside a .pkg file
For example, if you want to see the contents of /etc/systemd/logind.conf
supplied within the systemd package:
$ tar -xOf /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz etc/systemd/logind.conf
Or you can use vim, then browse the archive:
$ vim /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz
Find applications that use libraries from older packages
Even if you installed a package the existing long-running programs (like daemons and servers) still keep using code from old package libraries. And it is a bad idea to let these programs running if the old library contains a security bug.
Here is a way how to find all the programs that use old packages code:
# lsof +c 0 | grep -w DEL | awk '1 { print $1 ": " $NF }' | sort -u
It will print running program name and old library that was removed or replaced with newer content.