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{{Lowercase title}}
 
[[Category:Package management]]
 
[[Category:Package management]]
[[es:Pacman Tips]]
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[[es:Pacman/Tips and tricks]]
[[it:Pacman Tips]]
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[[fa:Pacman tips]]
[[ru:Pacman Tips]]
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[[fr:Astuces Pacman]]
[[tr:Pacman_ipuçları]]
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[[it:Pacman/Tips and tricks]]
[[zh-CN:Pacman Tips]]
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[[ja:Pacman ヒント]]
{{Article summary start|Summary}}
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[[pt:Pacman/Tips and tricks]]
{{Article summary text|This is a collection of common tips for new pacman users.}}
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[[ru:Pacman/Tips and tricks]]
{{Article summary heading|Related}}
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[[zh-hans:Pacman/Tips and tricks]]
{{Article summary wiki|pacman}}
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{{Related articles start}}
{{Article summary wiki|Mirrors}}
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{{Related|Mirrors}}
{{Article summary wiki|Creating Packages}}
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{{Related|Creating packages}}
{{Article summary wiki|Custom local repository}}
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{{Related articles end}}
{{Article summary end}}
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For general methods to improve the flexibility of the provided tips or ''pacman'' itself, see [[Core utilities]] and [[Bash]].
  
== Cosmetic and Convienence ==
+
== Maintenance ==
 +
 
 +
{{Expansion|{{ic|1=Usage=}} introduced with pacman 4.2, see [http://allanmcrae.com/2014/12/pacman-4-2-released/]}}
  
=== Color output ===
+
{{Note|Instead of using ''comm'' (which requires sorted input with ''sort'') in the sections below, you may also use {{ic|grep -Fxf}} or {{ic|grep -Fxvf}}.}}
  
As of version 4.1, Pacman has a color option. Uncomment the "Color" line in {{ic|pacman.conf}}.
+
See also [[System maintenance]].
  
=== Shortcuts ===
+
=== Listing packages ===
  
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.
+
You may want to get the list of installed packages with their version, which is useful when reporting bugs or discussing installed packages.
  
==== Configure the shell ====
+
* List all explicitly installed packages: {{ic|pacman -Qe}}.
 +
* List all packages in the group named {{ic|group}}: {{ic|pacman -Sg group}}
 +
* List all explicitly installed native packages (i.e. present in the sync database) that are not direct or optional dependencies: {{ic|pacman -Qent}}.
 +
* List all foreign packages (typically manually downloaded and installed or packages removed from the repositories): {{ic|pacman -Qm}}.
 +
* List all native packages (installed from the sync database(s)): {{ic|pacman -Qn}}.
 +
* List packages by regex: {{ic|pacman -Qs ''regex''}}.
 +
* List packages by regex with custom output format: {{ic|expac -s "%-30n %v" ''regex''}} (needs {{Pkg|expac}}).
  
Add the following examples, which work in both [[Bash]] and [[Zsh]]:
+
==== With size ====
{{bc|<nowiki> # Pacman alias examples
 
alias pacupg='sudo pacman -Syu'        # Synchronize with repositories before upgrading packages that are out of date on the local system.
 
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
 
  
# Additional pacman alias examples
+
Figuring out which packages are largest can be useful when trying to free space on your hard drive. There are two options here: get the size of individual packages, or get the size of packages and their dependencies.
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 of another package
 
alias pacmir='sudo pacman -Syy'                # Force refresh of all package lists after updating /etc/pacman.d/mirrorlist
 
</nowiki>}}
 
  
==== Usage ====
+
===== Individual packages =====
  
Perform the respective commands by simply typing the alias name. For example, to synchronize with repositories before upgrading packages that are out of date on the local system:
+
The following command will list all installed packages and their individual sizes:
$ 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 ====
+
$ pacman -Qi | awk '/^Name/{name=$3} /^Installed Size/{print $4$5, name}' | sort -h
  
The aliases used above are merely examples. By following the syntax samples above, rename the aliases as convenient. For example:
+
===== Packages and dependencies =====
  
alias pacrem='sudo pacman -Rns'
+
To list package sizes with their dependencies,
alias pacout='sudo pacman -Rns'
 
  
In the case above, the commands {{ic|pacrem}} and {{ic|pacout}} both call your shell to execute the same command.
+
* Install {{Pkg|expac}} and run {{ic|<nowiki>expac -H M '%m\t%n' | sort -h</nowiki>}}.
 +
* Run {{Pkg|pacgraph}} with the {{ic|-c}} option.
  
=== Operations and Bash syntax ===
+
To list the download size of several packages (leave {{ic|''packages''}} blank to list all packages):
  
In addition to pacman's standard set of features, there are ways to extend its usability through rudimentary [[Bash]] commands/syntax.
+
$ expac -S -H M '%k\t%n' ''packages''
  
* To install a number of packages sharing similar patterns in their names -- not the entire group nor all matching packages; eg. {{Pkg|kde}}:
+
To list explicitly installed packages not in {{Grp|base}} nor {{Grp|base-devel}} with size and description:
  
  # pacman -S kde-{applets,theme,tools}
+
  $ expac -H M "%011m\t%-20n\t%10d" $(comm -23 <(pacman -Qqen | sort) <(pacman -Qqg base base-devel | sort)) | sort -n
  
* Of course, that is not limited and can be expanded to however many levels needed:
+
To list the packages marked for upgrade with their download size
  
  # pacman -S kde-{ui-{kde,kdemod},kdeartwork}
+
  $ pacman -Quq|xargs expac -S -H M '%k\t%n' | sort -sh
  
* Sometimes, {{Ic|-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:
+
==== By date ====
  
# pacman -Ss '^vim-'
+
To list the 20 last installed packages with {{Pkg|expac}}, run:
  
* pacman has the {{ic|-q}} operand to hide the version column, so it is possible to query and reinstall packages with "compiz" as part of their name:
+
$ expac --timefmt='%Y-%m-%d %T' '%l\t%n' | sort | tail -n 20
  
# pacman -S $(pacman -Qq | grep compiz)
+
or, with seconds since the epoch (1970-01-01 UTC):
  
== Maintenance ==
+
$ expac --timefmt=%s '%l\t%n' | sort -n | tail -n 20
  
''House keeping, in the interest of keeping a clean system and following [[The Arch Way]]''
+
==== Not in a specified group or repository ====
  
=== Listing all installed packages with size ===
+
{{Note|To get a list of packages installed as dependencies but no longer required by any installed package, see [[#Removing unused packages (orphans)]].}}
  
* You may want to get the list of installed packages sorted by size, which may be useful when freeing space on your hard drive.
+
List explicitly installed packages not in the {{Grp|base}} or {{Grp|base-devel}} groups:
* Use {{ic|pacsysclean}} from {{Pkg|pacman}} package.
 
* Install {{Pkg|expac}} and run {{ic| expac -s "%-30n %m" | sort -rhk 2}}
 
* 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].
 
  
=== Identify files not owned by any package ===
+
$ comm -23 <(pacman -Qeq | sort) <(pacman -Qgq base base-devel | sort)
  
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. {{ic|./configure && make && make install}}). Search the file-system for these files (or symlinks) using this simple script:
+
List all installed packages unrequired by other packages, and which are not in the {{Grp|base}} or {{Grp|base-devel}} groups:
  
{{hc|pacman-disowned|<nowiki>
+
$ comm -23 <(pacman -Qqt | sort) <(pacman -Sqg base base-devel | sort)
#!/bin/sh
 
  
tmp=${TMPDIR-/tmp}/pacman-disowned-$UID-$$
+
As above, but with descriptions:
db=$tmp/db
 
fs=$tmp/fs
 
  
mkdir "$tmp"
+
$ expac -HM '%-20n\t%10d' $(comm -23 <(pacman -Qqt | sort) <(pacman -Qqg base base-devel | sort))
trap 'rm -rf "$tmp"' EXIT
 
  
pacman -Qlq | sort -u > "$db"
+
List all installed packages that are ''not'' in the specified repository ''repo_name''
  
find /bin /etc /sbin /usr \
+
$ comm -23 <(pacman -Qq | sort) <(pacman -Slq ''repo_name'' | sort)
  ! -name lost+found \
 
  \( -type d -printf '%p/\n' -o -print \) | sort > "$fs"
 
  
comm -23 "$fs" "$db"</nowiki>}}
+
List all installed packages that are in the ''repo_name'' repository:
  
To generate the list:
+
$ comm -12 <(pacman -Qq | sort) <(pacman -Slq ''repo_name'' | sort)
  
$ pacman-disowned > non-db.txt
+
List all packages on the Arch Linux ISO that are not in the base group:
  
Note that one should '''not''' delete all files listed in {{ic|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 {{Ic|grep}}.
+
<nowiki>$ comm -23 <(curl https://git.archlinux.org/archiso.git/plain/configs/releng/packages.both) <(pacman -Qqg base | sort)</nowiki>
  
=== Removing orphaned packages ===
+
==== Development packages ====
  
For ''recursively'' removing orphans:
+
To list all development/unstable packages, run:
  
{{bc|# pacman -Rs $(pacman -Qtdq)}}
+
$ pacman -Qq | grep -Ee '-(bzr|cvs|darcs|git|hg|svn)$'
  
The following '''alias''' is easily inserted into {{ic|~/.bashrc}} and removes orphans if found:
+
=== Listing files owned by a package with size ===
  
{{hc|~/.bashrc|<nowiki># '[r]emove [o]rphans' - recursively remove ALL orphaned packages
+
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.
alias pacro="/usr/bin/pacman -Qtdq &gt; /dev/null &amp;&amp; sudo /usr/bin/pacman -Rs \$(/usr/bin/pacman -Qtdq | sed -e ':a;N;\$!ba;s/\n/ /g')"</nowiki>}}
 
  
The following '''function''' is easily inserted into {{ic|~/.bashrc}} and removes orphans if found:
+
$ pacman -Qlq ''package'' | grep -v '/$' | xargs du -h | sort -h
  
{{hc|~/.bashrc|<nowiki>
+
=== Identify files not owned by any package ===
orphans() {
 
  if [[ ! -n $(pacman -Qdt) ]]; then
 
    echo "No orphans to remove."
 
  else
 
    sudo pacman -Rs $(pacman -Qdtq)
 
  fi
 
}</nowiki>}}
 
  
=== Removing everything but base group ===
+
If your system has stray files not owned by any package (a common case if you do not [[Enhance system stability#Use the package manager to install software|use the package manager to install software]]), you may want to find such files in order to clean them up.
  
If it is ever necessary to remove all packages except the base group, try this one liner:
+
One method is to use {{ic|# pacreport --unowned-files}} from {{Pkg|pacutils}} which will list unowned files among other details.
  
# pacman -Rs $(comm -23 <(pacman -Qeq|sort) <((for i in $(pacman -Qqg base); do pactree -ul $i; done)|sort -u|cut -d ' ' -f 1))
+
Another is to list all files of interest and check them against pacman:
  
Source: [https://bbs.archlinux.org/viewtopic.php?id=130176 Look at discussion here]
+
# find /etc /usr /opt /var | LC_ALL=C pacman -Qqo - 2>&1 > /dev/null | cut -d ' ' -f 5-
  
Notes:
+
{{Tip|The {{Pkg|lostfiles}} script performs similar steps, but also includes an extensive blacklist to remove common false positives from the output.}}
  
# {{ic|comm}} requires sorted input otherwise you get e.g. {{ic|comm: file 1 is not in sorted order}}.
+
=== Tracking unowned files created by packages ===
# {{ic|pactree}} prints the package name followed by what it provides. For example:
 
  
{{hc|$ pactree -lu logrotate|
+
Most systems will slowly collect several [http://ftp.rpm.org/max-rpm/s1-rpm-inside-files-list-directives.html#S3-RPM-INSIDE-FLIST-GHOST-DIRECTIVE ghost] files such as state files, logs, indexes, etc. through the course of usual operation.
logrotate
 
popt
 
glibc
 
linux-api-headers
 
tzdata
 
dcron cron
 
bash
 
readline
 
ncurses
 
gzip}}
 
  
The {{ic|dcron cron}} line seems to cause problems, that is why {{ic|cut -d ' ' -f 1}} is needed - to keep just the package name.
+
{{ic|pacreport}} from {{Pkg|pacutils}} can be used to track these files and their associations via {{ic|/etc/pacreport.conf}} (see {{man|1|pacreport|FILES}}).
  
=== Listing official installed packages only ===
+
An example may look something like this (abridged):
  
pacman -Qq |grep -Fv -f <(pacman -Qqm)
+
{{hc|/etc/pacreport.conf|<nowiki>
 +
[Options]
 +
IgnoreUnowned = usr/share/applications/mimeinfo.cache
  
=== Getting the dependencies list of several packages ===
+
[PkgIgnoreUnowned]
 +
alsa-utils = var/lib/alsa/asound.state
 +
bluez = var/lib/bluetooth
 +
ca-certificates = etc/ca-certificates/trust-source/*
 +
dbus = var/lib/dbus/machine-id
 +
glibc = etc/ld.so.cache
 +
grub = boot/grub/*
 +
linux = boot/initramfs-linux.img
 +
pacman = var/lib/pacman/local
 +
update-mime-database = usr/share/mime/magic
 +
</nowiki>}}
  
Dependencies are alphabetically sorted and doubles are removed.
+
Then, when using {{ic|# pacreport --unowned-files}}, any unowned files will be listed if the associated package is no longer installed (or if any new files have been created).
Note that you can use {{ic|pacman -Qi}} to improve response time a little. But
 
you won't be able to query as many packages. Unfound packages are simply skipped
 
(hence the {{ic|2>/dev/null}}).
 
You can get dependencies of AUR packages as well if you use {{ic|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
+
Additionally, [https://github.com/CyberShadow/aconfmgr aconfmgr] ({{AUR|aconfmgr-git}}) allows tracking modified and orphaned files using a configuration script.
  
Alternatively, you can use {{ic|expac}}: {{ic|expac -l '\n' %E -S $@ &#124; sort -u}}.
+
=== Removing unused packages (orphans) ===
  
=== Getting the size of several packages ===
+
For recursively removing orphans and their configuration files:
  
You can use (and tweak) this little shell function:
+
# pacman -Rns $(pacman -Qtdq)
  
{{hc|~/.bashrc|<nowiki>
+
If no orphans were found ''pacman'' outputs {{ic|error: no targets specified}}. This is expected as no arguments were passed to {{ic|pacman -Rns}}.
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)}'
 
}</nowiki>}}
 
  
As told for the dependencies list, you can use {{ic|pacman -Qi}} instead, but
+
{{Note|The arguments {{ic|-Qt}} list only true orphans. To include packages which are ''optionally'' required by another package, pass the {{ic|-t}} flag twice (''i.e.'', {{ic|-Qtt}}).}}
not [[yaourt]] since AUR's PKGBUILD do not have size information.
 
  
A nice one-liner:
+
=== Removing everything but base group ===
  
$ 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)}')
+
If it is ever necessary to remove all packages except the base group, try this one-liner (requires {{Pkg|pacman-contrib}}):
  
You should replace "$@" with packages, or put this line in a shell function.
+
# pacman -R $(comm -23 <(pacman -Qq | sort) <((for i in $(pacman -Qqg base); do pactree -ul "$i"; done) | sort -u))
  
=== Listing changed configuration files ===
+
The one-liner was originally devised in [https://bbs.archlinux.org/viewtopic.php?id=130176 this discussion], and later improved in this article.
If you want to backup your system configuration files you could copy all files in {{ic|/etc/}}, but usually you're 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.
 
{{hc|changed-files.sh|<nowiki>
 
#!/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
 
</nowiki>}}
 
  
=== Listing all packages that nothing else depends on ===
+
=== Getting the dependencies list of several packages ===
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.
 
  
{{hc|clean|<nowiki>
+
Dependencies are alphabetically sorted and doubles are removed.
#!/bin/bash
 
  
# This script is designed to help you clean your computer from unneeded
+
{{Note|To only show the tree of local installed packages, use {{ic|pacman -Qi}}.}}
# 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
+
$ pacman -Si ''packages'' | awk -F'[:<=>]' '/^Depends/ {print $2}' | xargs -n1 | sort -u
# not be included in the list of unrequired packages later.
 
ignoregrp="base base-devel"
 
ignorepkg=""
 
  
# Temporary file locations
+
Alternatively, with {{Pkg|expac}}:
tmpdir=/tmp
 
ignored=$tmpdir/ignored
 
installed=$tmpdir/installed
 
  
# Generate list of installed packages and packages you wish to keep.
+
$ expac -l '\n' %E -S ''packages'' | sort -u
echo $(pacman -Sg $ignoregrp | awk '{print $2}') $ignorepkg | tr ' ' '\n' | sort | uniq > $ignored
 
pacman -Qq | sort > $installed
 
  
# Do not loop packages you are keeping
+
=== Listing changed backup files ===
loop=$(comm -13 $ignored $installed)
 
  
# Check each remaining package. If package is not required by anything and
+
If you want to backup your system configuration files you could copy all files in {{ic|/etc/}}, but usually you are only interested in the files that you have changed. Modified [[Pacnew_and_Pacsave_files#Package_backup_files|backup files]] can be viewed with the following command:
# is not on your ignore list, print the package name to the screen.
 
for line in $loop; do
 
  check=$(pacman -Qi $line | awk '/Required By/ {print $4}')
 
  if [ "$check" == 'None' ]; then echo $line; fi
 
done
 
  
# Clean up $tmpdir
+
# pacman -Qii | awk '/^MODIFIED/ {print $2}'
rm $ignored $installed
+
 
</nowiki>}}
+
Running this command with root permissions will ensure that files readable only by root (such as {{ic|/etc/sudoers}}) are included in the output.
  
If you install {{pkg|expac}} you can run {{ic|<nowiki>expac "%n %N" -Q $(expac "%n %G" | grep -v ' base') | awk '$2 == "" {print $1}'</nowiki>}} which should give the same results but much faster.
+
{{Tip|See [[#Listing all changed files from packages]] to list all changed files ''pacman'' knows about, not only backup files.}}
  
=== Backing up Local database with Systemd ===
+
=== Backup the pacman database ===
  
[https://wiki.archlinux.org/index.php/Systemd Systemd] can take snapshots of the pacman local database everytime it is modified.
+
The following command can be used to backup the local ''pacman'' database:
  
{{Note| There is a more configurable version in the AUR: {{AUR|pakbak-git}}}}
+
$ tar -cjf pacman_database.tar.bz2 /var/lib/pacman/local
{{Tip| Save the following script as {{ic|/usr/lib/systemd/scripts/pakbak_script}}.}}
 
{{Note| Change the value of {{ic|$pakbak}} to modify where the backed up database is stored.}}
 
{{bc|<nowiki>
 
#!/bin/bash
 
  
declare -r pakbak="/pakbak.tar.xz";  ## set backup location
+
Store the backup ''pacman'' database file on one or more offline media, such as a USB stick, external hard drive, or CD-R.
tar -cJf "$pakbak" "/var/lib/pacman/local";  ## compress & store pacman local database in $pakbak
 
</nowiki>}}
 
  
{{Tip|Save the following [https://wiki.archlinux.org/index.php/Systemd#Writing_custom_.service_files service file] as {{ic|/usr/lib/systemd/system/pakbak.service}}.}}
+
The database can be restored by moving the {{ic|pacman_database.tar.bz2}} file into the {{ic|/}} directory and executing the following command:
{{bc|<nowiki>
 
[Unit]
 
Description=Back up pacman database
 
  
[Service]
+
# tar -xjvf pacman_database.tar.bz2
Type=oneshot
 
ExecStart=/bin/bash /usr/lib/systemd/scripts/pakbak_script
 
RemainAfterExit=no
 
</nowiki>}}
 
  
{{Tip|Save the following [https://wiki.archlinux.org/index.php/Systemd#Writing_custom_.service_files path] file as {{ic|/usr/lib/systemd/system/pakbak.path}}.}}
+
{{Note|If the ''pacman'' database files are corrupted, and there is no backup file available, there exists some hope of rebuilding the ''pacman'' database. Consult [[#Restore pacman's local database]].}}
{{bc|<nowiki>
 
[Unit]
 
Description=Back up pacman database
 
  
[Path]
+
{{Tip|The {{AUR|pakbak-git}} package provides a script and a [[systemd]] service to automate the task. Configuration is possible in {{ic|/etc/pakbak.conf}}.}}
PathChanged=/var/lib/pacman/local
 
Unit=pakbak.service
 
  
[Install]
+
=== Check changelogs easily ===
WantedBy=multi-user.target
 
</nowiki>}}
 
  
{{Tip|To start the backup service :
+
When maintainers update packages, commits are often commented in a useful fashion. Users can quickly check these from the command line by installing {{AUR|pacolog}}. This utility lists recent commit messages for packages from the official repositories or the AUR, by using {{ic|pacolog <package>}}.
{{bc|<nowiki>
 
# systemctl start pakbak.path
 
</nowiki>}}
 
To enable the backup service automatically on reboot :
 
{{bc|<nowiki>
 
# systemctl enable pakbak.path
 
</nowiki>}}
 
}}
 
  
 
== Installation and recovery ==
 
== Installation and recovery ==
  
''Alternative ways of getting and restoring packages.''
+
Alternative ways of getting and restoring packages.
  
 
=== Installing packages from a CD/DVD or USB stick ===
 
=== Installing packages from a CD/DVD or USB stick ===
 +
 +
{{Merge|#Custom local repository|Use as an example and avoid duplication}}
  
 
To download packages, or groups of packages:
 
To download packages, or groups of packages:
Line 347: Line 238:
 
  # mount /dev/sdxY /mnt/repo  #For a USB stick.
 
  # mount /dev/sdxY /mnt/repo  #For a USB stick.
  
'''2.''' Edit {{ic|pacman.conf}} and add this repository ''before'' the other ones (e.g. extra, core, etc.). This is important. Don't 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:
+
'''2.''' Edit {{ic|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:
  
{{hc|# nano /etc/pacman.conf|2=
+
{{hc|/etc/pacman.conf|2=
 
[custom]
 
[custom]
 
SigLevel = PackageRequired
 
SigLevel = PackageRequired
 
Server = file:///mnt/repo/Packages}}
 
Server = file:///mnt/repo/Packages}}
  
'''3.''' Finally, synchronize the pacman database to be able to use the new repository:
+
'''3.''' Finally, synchronize the ''pacman'' database to be able to use the new repository:
  
  # pacman -Sy
+
  # pacman -Syu
  
 
=== Custom local repository ===
 
=== Custom local repository ===
  
pacman 3 introduced a new script named {{ic|repo-add}} which makes generating a database for a personal repository much easier. Use {{ic|repo-add --help}} for more details on its usage.
+
Use the ''repo-add'' script included with ''pacman'' to generate a database for a personal repository. Use {{ic|repo-add --help}} for more details on its usage. 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/package-1.0-1-x86_64.pkg.tar.xz''
  
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):
+
{{Note|A package database is a tar file, optionally compressed. Valid extensions are ''.db'' or ''.files'' followed by an archive extension of ''.tar'', ''.tar.gz'', ''.tar.bz2'', ''.tar.xz'', or ''.tar.Z''. The file does not need to exist, but all parent directories must exist.}}
  
$ repo-add /path/to/repo.db.tar.gz /path/to/*.pkg.tar.xz
+
The database and the packages do not need to be in the same directory when using ''repo-add'', but keep in mind that when using ''pacman'' with that database, they should be together. Storing all the built packages to be included in the repository in one directory also allows to use shell glob expansion to add or update multiple packages at once:
  
Note that when using {{ic|repo-add}}, the database and the packages do not need to be in the same directory. But when using pacman with that database, they should be together.
+
$ repo-add ''/path/to/repo.db.tar.gz /path/to/*.pkg.tar.xz''
  
To add a new package (and remove the old if it exists), run:
+
{{Warning|''repo-add'' adds the entries into the database in the same order as passed on the command line. If multiple versions of the same package are involved, care must be taken to ensure that the correct version is added last. In particular, note that lexical order used by the shell depends on the locale and differs from the [https://www.archlinux.org/pacman/vercmp.8.html vercmp] ordering used by ''pacman''.}}
  
$ repo-add /path/to/repo.db.tar.gz /path/to/packagetoadd-1.0-1-i686.pkg.tar.xz
+
''repo-remove'' is used to remove packages from the package database, except that only package names are specified on the command line.
  
{{Note|If there is a package that needs to be removed from the repository, read up on {{Ic|repo-remove}}.}}
+
$ repo-remove ''/path/to/repo.db.tar.gz pkgname''
  
Once the local repository has been made, add the repository to {{ic|pacman.conf}}. The name of the {{ic|db.tar.gz}} file is the repository name. Reference it directly using a {{ic|file://}} url, or access it via FTP using ftp://localhost/path/to/directory.
+
Once the local repository database has been created, add the repository to {{ic|pacman.conf}} for each system that is to use the repository. An example of a custom repository is in {{ic|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 {{ic|file://}} url, or via FTP using ftp://localhost/path/to/directory.
  
 
If willing, add the custom repository to the [[Unofficial user repositories|list of unofficial user repositories]], so that the community can benefit from it.
 
If willing, add the custom repository to the [[Unofficial user repositories|list of unofficial user repositories]], so that the community can benefit from it.
  
 
=== Network shared pacman cache ===
 
=== Network shared pacman cache ===
 +
 +
If you happen to run several Arch boxes on your LAN, you can share packages so that you can greatly decrease your download times. Keep in mind you should not share between different architectures (i.e. i686 and x86_64) or you will run into problems.
  
 
==== Read-only cache ====
 
==== Read-only cache ====
  
If you're looking for a quick and dirty solution, you can simply run a standalone webserver which other computers can use as a first mirror: {{ic|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.
+
If you are looking for a quick solution, you can simply run a standalone webserver which other computers can use as a first mirror:
 +
# ln -s /var/lib/pacman/sync/*.db /var/cache/pacman/pkg
 +
$ sudo -u http darkhttpd /var/cache/pacman/pkg --no-server-id
 +
You could also run darkhttpd as a systemd service for convenience. Just add this server at the top of your {{ic|/etc/pacman.d/mirrorlist}} in client machines with {{ic|1=Server = http&#58;//mymirror:8080}}. Make sure to keep your mirror updated.
 +
 
 +
If you're already running a web server for some other purpose, you might wish to reuse that as your local repo server instead of darkhttpd. For example, say you already serve a site with [[nginx]], you can add an nginx server block listening on port 8080:
 +
 
 +
{{hc|/etc/nginx/nginx.conf|
 +
http {
 +
    # ... other nginx server configs up here
 +
 
 +
    server {
 +
        listen 8080;
 +
        root /var/cache/pacman/pkg;
 +
        server_name myarchrepo.localdomain;
 +
        try_files $uri $uri/;
 +
    }
 +
}
 +
}}
 +
 
 +
Remember to restart nginx after making this change.
 +
 
 +
Whichever web server you use, remember to open port 8080 to local traffic (and you probably want to deny anything not local), so add a rule like the following to [[iptables]]:
 +
 
 +
{{hc|/etc/iptables/iptables.rules|
 +
-A TCP -s 192.168.0.0/16 -p tcp -m tcp --dport 8080 -j ACCEPT
 +
}}
 +
 
 +
Remember to restart iptables after making this change.
 +
 
 +
==== Distributed read-only cache ====
 +
 
 +
There are Arch-specific tools for automatically discovering other computers on your network offering a package cache. Try {{Pkg|pacredir}}, [[pacserve]], {{AUR|pkgdistcache}}, or {{AUR|paclan}}. pkgdistcache uses Avahi instead of plain UDP which may work better in certain home networks that route instead of bridge between WiFi and Ethernet.
 +
 
 +
Historically, there was [https://bbs.archlinux.org/viewtopic.php?id=64391 PkgD] and [https://github.com/toofishes/multipkg multipkg], but they are no longer maintained.
  
 
==== Read-write cache ====
 
==== Read-write cache ====
  
{{Tip|See [http://xyne.archlinux.ca/projects/pacserve/ pacserve] for an alternative (and probably simpler) solution than what follows.}}
+
In order to share packages between multiple computers, simply share {{ic|/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 packages: {{pkg|shfs-utils}}, {{pkg|sshfs}}, {{pkg|curlftpfs}}, {{pkg|samba}} or {{pkg|nfs-utils}}.
 +
 
 +
{{Tip|
 +
* To use ''sshfs'' or ''shfs'', consider reading [[Using SSH Keys]].
 +
* By default, ''smbfs'' does not serve filenames that contain colons, which results in the client downloading the offending package afresh. To prevent this, use the {{ic|mapchars}} mount option on the client.
 +
}}
 +
 
 +
Then, to share the actual packages, mount {{ic|/var/cache/pacman/pkg}} from the server to {{ic|/var/cache/pacman/pkg}} on every client machine.
 +
 
 +
{{Warning|Do not make {{ic|/var/cache/pacman/pkg}} or any of its ancestors (e.g., {{ic|/var}}) a symlink. ''Pacman'' expects these to be directories. When ''pacman'' re-installs or upgrades itself, it will remove the symlinks and create empty directories instead. However during the transaction ''pacman'' relies on some files residing there, hence breaking the update process. Refer to {{bug|50298}} for further details.}}
  
In order to share packages between multiple computers, simply share {{ic|/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.
+
==== two-way with rsync ====
  
First, install any network-supporting filesystem; for example [[sshfs]], [[shfs]], [[ftpfs]], [[smbfs]] or [[nfs]].
+
Another approach in a local environment is [[rsync]]. Choose a server for caching and enable the [[Rsync#rsync daemon]]. On clients synchronize two-way with this share via rsync protocol. Filenames that contain colons are no problem for the rsync protocol.
  
{{Tip|To use sshfs or shfs, consider reading [[Using SSH Keys]].}}
+
Draft example for a client, using {{ic|uname -m}} within the share name ensures an architecture dependant sync:
 +
  # rsync rsync://server/share_$(uname -m)/ /var/cache/pacman/pkg/ ...
 +
  # pacman ...
 +
  # paccache ...
 +
  # rsync /var/cache/pacman/pkg/ rsync://server/share_$(uname -m)/  ...
  
Then, to share the actual packages, mount {{ic|/var/cache/pacman/pkg}} from the server to {{ic|/var/cache/pacman/pkg}} on every client machine.
+
==== Dynamic reverse proxy cache using nginx ====
  
To have shared package databases, mount {{ic|/var/lib/pacman/sync/{core,extra,testing,community} }} in the same way. Proceed to place the appropriate lines in {{ic|/etc/fstab}}.
+
[[nginx]] can be used to proxy requests to official upstream mirrors and cache the results to local disk. All subsequent requests for that file will be served directly from the local cache, minimizing the amount of internet traffic needed to update a large number of servers with minimal effort.  
  
==== Preventing unwanted cache purges ====
+
{{Warning| This method has a limitation. You must use mirrors that use the same relative path to package files and you must configure your cache to use that same path. In this example, we are using mirrors that use the relative path {{ic|/archlinux/$repo/os/$arch}} and our cache's {{ic|Server}} setting in {{ic|mirrorlist}} is configured similarly.}}
  
By default, {{Ic|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.
+
In this example, we will run the cache server on {{ic|<nowiki>http://cache.domain.example:8080/</nowiki>}} and storing the packages in {{ic|/srv/http/pacman-cache/}}.  
  
To clean up the cache so that only ''outdated'' tarballs are deleted, add this entry in the {{ic|[options]}} section of {{ic|/etc/pacman.conf}}:
+
Create the directory for the cache and adjust the permissions so nginx can write files to it:
  
CleanMethod = KeepCurrent
+
  # mkdir /srv/http/pacman-cache
 +
  # chown http:http /srv/http/pacman-cache
  
=== Backing up and retrieving a list of installed packages ===
+
Next, configure nginx as the [https://gist.github.com/anonymous/97ec4148f643de925e433bed3dc7ee7d dynamic cache] (read the comments for an explanation of the commands).
  
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.
+
Finally, update your other Arch Linux servers to use this new cache by adding the following line to the {{ic|mirrorlist}} file:
  
* First, backup the current list of non-local packages:
+
{{hc|/etc/pacman.d/mirrorlist|<nowiki>
 +
Server = http://cache.domain.example:8080/archlinux/$repo/os/$arch
 +
...
 +
</nowiki>}}
  
: $ comm -23 <(pacman -Qeq|sort) <(pacman -Qmq|sort) > pkglist.txt
+
{{Note| You will need to create a method to clear old packages, as this directory will continue to grow over time. {{ic|paccache}} (which is provided by {{pkg|pacman-contrib}}) can be used to automate this using retention criteria of your choosing. For example, {{ic|find /srv/http/pacman-cache/ -type d -exec paccache -v -r -k 2 -c {} \;}} will keep the last 2 versions of packages in your cache directory.}}
  
* Store the {{ic|pkglist.txt}} on a USB key or other convenient medium or gist.github.com or Evernote, Dropbox, etc.
+
==== Synchronize pacman package cache using synchronization programs ====
  
* Copy the {{ic|pkglist.txt}} file to the new installation, and navigate to the directory containing it.
+
Use [[Syncthing]] or [[Resilio Sync]] to synchronize the ''pacman'' cache folders (i.e. {{ic|/var/cache/pacman/pkg}}).
  
* Issue the following command to install from the backup list:
+
==== Preventing unwanted cache purges ====
  
: # pacman -S $(< pkglist.txt)
+
By default, {{Ic|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.
  
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).
+
To clean up the cache so that only ''outdated'' tarballs are deleted, add this entry in the {{ic|[options]}} section of {{ic|/etc/pacman.conf}}:
  
In such a case, you may still want to install all available packages from that list:
+
CleanMethod = KeepCurrent
  
# pacman -S --needed $(comm -12 <(pacman -Slq|sort) <(sort badpkdlist) )
+
=== Recreate a package from the file system ===
  
Explanation:
+
To recreate a package from the file system, use {{AUR|fakepkg}}. 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 Linux Archive]] for alternatives.
  
* {{ic|pacman -Slq}} lists all available softwares, but the list is sorted by repository first, hence the {{ic|sort}} command.
+
=== List of installed packages ===
* Sorted files are required in order to make the {{ic|comm}} command work.
 
* The {{ic|-12}} parameter display lines common to both entries.
 
* The {{ic|--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):
+
Keeping a list of all the explicitly installed packages can be useful, to backup a system for example or speed up installation on a new system:
  
  $ yaourt -S --needed $(comm -13 <(pacman -Slq|sort) <(sort badpkdlist) )
+
  $ pacman -Qqe > pkglist.txt
  
Finally, you may want to remove all the packages on your system that are not mentioned in the list.
+
{{Note|
 +
* With option {{ic|-t}}, the packages already required by other explicitly installed packages are not mentioned. If reinstalling from this list they will be installed but as dependencies only.
 +
* With option {{ic|-n}}, foreign packages (e.g. from [[AUR]]) would be omitted from the list.
 +
* Use {{ic|comm -13 <(pacman -Qqdt {{!}} sort) < (pacman -Qqdtt {{!}} sort) > optdeplist.txt}} to also create a list of the installed optional dependencies which can be reinstalled with {{ic|--asdeps}}.
 +
* Use {{ic|pacman -Qqem > foreignpkglist.txt}} to create the list of AUR and other foreign packages that have been explicitly installed.}}
  
{{Warning|Use this command wisely, and always check the result prompted by pacman.}}
+
To keep an up-to-date list of explicitly installed packages (e.g. in combination with a versioned {{ic|/etc/}}), you can set up a [[Pacman#Hooks|hook]]. Example:
  
  # pacman -Rsu $(comm -23 <(pacman -Qq|sort) <(sort pkglist))
+
  [Trigger]
 +
Operation = Install
 +
Operation = Remove
 +
Type = Package
 +
Target = *
 +
 +
[Action]
 +
When = PostTransaction
 +
Exec = /bin/sh -c '/usr/bin/pacman -Qqe > /etc/pkglist.txt'
  
=== List downloaded packages that are not in base or base-devel ===
+
=== Install packages from a list ===
  
The following command will list any installed packages that are not in base/base-devel, and as such were likely installed manually by the user:
+
To install packages from a previously saved list of packages, while not reinstalling previously installed packages that are already up-to-date, run:
  
  $ comm -23 <(pacman -Qeq|sort) <(pacman -Qgq base base-devel|sort)
+
  # pacman -S --needed - < pkglist.txt
  
=== Reinstalling all installed packages ===
+
However, it is likely foreign packages such as from the AUR or installed locally are present in the list. To filter out from the list the foreign packages, the previous command line can be enriched as follows:
  
If you mess up your system ({{ic|rm -rf}}) you can repair by having pacman reinstall all of your packages.  
+
# pacman -S --needed $(comm -12 <(pacman -Slq | sort) <(sort pkglist.txt))
  
If your system does not contain any foreign (AUR) packages you can run:
+
Eventually, to make sure the installed packages of your system match the list and remove all the packages that are not mentioned in it:
  
  # pacman -Qeq | pacman -S -
+
  # pacman -Rsu $(comm -23 <(pacman -Qq | sort) <(sort pkglist.txt))
  
Pacman preserves the installation reason by default.
+
{{Tip|These tasks can be automated. See {{AUR|bacpac}}, {{AUR|packup}}, {{AUR|pacmanity}}, and {{AUR|pug}} for examples.}}
  
If you have foreign packages this will error as packages will not be found in the repositories. The following will make a list of all packages and remove the foreign packages seen with {{ic|pacman -Qmq}}. Combining a command to list all packages, and another to hide the list of foreign packages is required.
+
=== Listing all changed files from packages ===
  
The following will reinstall every package found in the repositories:
+
If you are suspecting file corruption (e.g. by software/hardware failure), but are unsure if files were corrupted, you might want to compare with the hash sums in the packages. This can be done with {{Pkg|pacutils}}:
  
  # comm -23 <(pacman -Qeq|sort) <(pacman -Qmq|sort) | pacman -S -
+
  # paccheck --md5sum --quiet
  
=== Restore pacman's local database ===
+
For recovery of the database see [[#Restore pacman's local database]]. The {{ic|mtree}} files can also be [[#Viewing a single file inside a .pkg file|extracted as {{ic|.MTREE}} from the respective package files]].
  
Signs that pacman needs a local database restoration:
+
{{Note|This should '''not''' be used as is when suspecting malicious changes! In this case security precautions such as using a live medium and an independent source for the hash sums are advised.}}
  
* {{ic|pacman -Q}} gives absolutely no output, and {{Ic|pacman -Syu}} erroneously reports that the system is up to date.
+
=== Reinstalling all packages ===
* When trying to install a package using {{ic|pacman -S package}}, and it outputs a list of already satisfied dependencies.
+
To reinstall all native packages, use:
* When {{ic|testdb}} (part of {{Pkg|pacman}}) reports database inconsistency.
 
  
Most likely, pacman's database of installed software, {{ic|/var/lib/pacman/local}}, has been corrupted or deleted. While this is a serious problem, it can be restored by following the instructions below.
+
# pacman -Qqn | pacman -S -
  
Firstly, make sure pacman's log file is present:
+
Foreign (AUR) packages must be reinstalled separately; you can list them with {{ic|pacman -Qqm}}.
  
$ ls /var/log/pacman.log
+
''Pacman'' preserves the [[installation reason]] by default.
  
If it does not exist, it is ''not'' possible to continue with this method. You may be able to use [https://bbs.archlinux.org/viewtopic.php?pid=670876 Xyne's package detection script] to recreate the database. If not, then the likely solution is to re-install the entire system.
+
=== Restore pacman's local database ===
  
==== Log filter script ====
+
See [[Pacman/Restore local database]].
{{hc|pacrecover|<nowiki>
 
#!/bin/bash -e
 
  
. /etc/makepkg.conf
+
=== Recovering a USB key from existing install ===
  
PKGCACHE=$((grep -m 1 '^CacheDir' /etc/pacman.conf || echo 'CacheDir = /var/cache/pacman/pkg') | sed 's/CacheDir = //')
+
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 {{ic|/newarch}})
  
pkgdirs=("$@" "$PKGDEST" "$PKGCACHE")
+
# pacman -S $(pacman -Qq --dbpath /newarch/var/lib/pacman) --root /newarch --dbpath /newarch/var/lib/pacman
  
while read -r -a parampart; do
+
=== Viewing a single file inside a .pkg file ===
  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
 
</nowiki>}}
 
 
Make the script executable:
 
  
$ chmod +x pacrecover
+
For example, if you want to see the contents of {{ic|/etc/systemd/logind.conf}} supplied within the {{Pkg|systemd}} package:
  
==== Generating the package recovery list ====
+
$ tar -xOf /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz etc/systemd/logind.conf
  
{{Warning|If for some reason your [[pacman]] cache or [[makepkg]] package destination contain packages for other architectures, remove them before continuation.}}
+
Or you can use {{pkg|vim}} to browse the archive:
  
Run the script (optionally passing additional directories with packages as parameters):
+
$ vim /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz
  
$ paclog-pkglist /var/log/pacman.log | ./pacrecover >files.list 2>pkglist.orig
+
=== Find applications that use libraries from older packages ===
  
This way two files will be created: {{Ic|files.list}} with package files, still present on machine and {{Ic|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.
+
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 to automatically restrict second list to packages available in a repository:
+
Here is a way how to find all the programs that use old packages code:
  
  $ { cat pkglist.orig; pacman -Slq; } | sort | uniq -d > pkglist
+
  # 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.
  
Check if some important ''base'' package are missing, and add them to the list:
+
== Performance ==
  
$ comm -23 <(pacman -Sgq base) pkglist.orig >> pkglist
+
=== Download speeds ===
  
Proceed once the contents of both lists are satisfactory, since they will be used to restore pacman's installed package database; {{ic|/var/lib/pacman/local/}}.
+
{{Note|If your download speeds have been reduced to a crawl, ensure you are using one of the many [[mirrors]] and not ftp.archlinux.org, which is [https://www.archlinux.org/news/302/ throttled since  March 2007].}}
  
==== Performing the recovery ====
+
When downloading packages ''pacman'' uses the mirrors in the order they are in {{ic|/etc/pacman.d/mirrorlist}}. The mirror which is at the top of the list by default however may not be the fastest for you. To select a faster mirror, see [[Mirrors]].
  
Define bash alias for recovery purposes:
+
''Pacman''<nowiki>'</nowiki>s speed in downloading packages can also be improved by using a different application to download packages, instead of ''pacman''<nowiki>'</nowiki>s built-in file downloader.
  
# recovery-pacman() {
+
In all cases, make sure you have the latest ''pacman'' before doing any modifications.
    pacman "$@"      \
 
    --log /dev/null  \
 
    --noscriptlet    \
 
    --dbonly          \
 
    --force          \
 
    --nodeps          \
 
    --needed          \
 
    #
 
}
 
  
{{ic|--log /dev/null}} allows to avoid needless pollution of pacman log, {{Ic|--needed}} will save some time by skipping packages, already present in database, {{Ic|--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.
+
# pacman -Syu
  
Populate the sync database:
+
==== Powerpill ====
  
# pacman -Sy
+
[[Powerpill]] is a ''pacman'' wrapper that uses parallel and segmented downloading to try to speed up downloads for ''pacman''.
  
Start database generation by installing locally available package files from {{ic|files.list}}:
+
==== wget ====
  
# recovery-pacman -U $(< files.list)
+
This is also very handy if you need more powerful proxy settings than ''pacman''<nowiki>'</nowiki>s built-in capabilities.  
  
Install the rest from {{ic|pkglist}}:
+
To use {{ic|wget}}, first [[install]] the {{Pkg|wget}} package then modify {{ic|/etc/pacman.conf}} by uncommenting the following line in the {{ic|[options]}} section:
  
  # recovery-pacman -S $(< pkglist)
+
  XferCommand = /usr/bin/wget --passive-ftp -c -O %o %u
  
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.
+
Instead of uncommenting the {{ic|wget}} parameters in {{ic|/etc/pacman.conf}}, you can also modify the {{ic|wget}} configuration file directly (the system-wide file is {{ic|/etc/wgetrc}}, per user files are {{ic|$HOME/.wgetrc}}.
  
# pacman -D --asdeps $(pacman -Qq)
+
==== aria2 ====
# pacman -D --asexplicit $(pacman -Qtq)
 
  
Optionally check all installed packages for corruption:
+
[[aria2]] is a lightweight download utility with support for resumable and segmented HTTP/HTTPS and FTP downloads. aria2 allows for multiple and simultaneous HTTP/HTTPS and FTP connections to an Arch mirror, which should result in an increase in download speeds for both file and package retrieval.
  
# pacman -Qk
+
{{Note|Using aria2c in ''pacman''<nowiki>'</nowiki>s XferCommand will '''not''' result in parallel downloads of multiple packages. ''Pacman'' invokes the XferCommand with a single package at a time and waits for it to complete before invoking the next. To download multiple packages in parallel, see [[Powerpill]].}}
  
Optionally [[#Identify files not owned by any package]].
+
Install {{Pkg|aria2}}, then edit {{ic|/etc/pacman.conf}} by adding the following line to the {{ic|[options]}} section:
  
Update all packages:
+
XferCommand = /usr/bin/aria2c --allow-overwrite=true --continue=true --file-allocation=none --log-level=error --max-tries=2 --max-connection-per-server=2 --max-file-not-found=5 --min-split-size=5M --no-conf --remote-time=true --summary-interval=60 --timeout=5 --dir=/ --out %o %u
  
# pacman -Su
+
{{Tip|1=[https://bbs.archlinux.org/viewtopic.php?pid=1491879#p1491879 This alternative configuration for using ''pacman'' with aria2] tries to simplify configuration and adds more configuration options.}}
  
=== Recovering a USB key from existing install ===
+
See [http://aria2.sourceforge.net/manual/en/html/aria2c.html#options OPTIONS] in {{man|1|aria2c}} for used aria2c options.
  
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)
+
* {{ic|-d, --dir}}: The directory to store the downloaded file(s) as specified by ''pacman''.
 +
* {{ic|-o, --out}}: The output file name(s) of the downloaded file(s).
 +
* {{ic|%o}}: Variable which represents the local filename(s) as specified by ''pacman''.
 +
* {{ic|%u}}: Variable which represents the download URL as specified by ''pacman''.
  
# pacman -S $(pacman -Qq --dbpath /newarch/var/lib/pacman) --root /newarch --dbpath /newarch/var/lib/pacman
+
==== Other applications ====
  
=== Extracting contents of a .pkg file ===
+
There are other downloading applications that you can use with ''pacman''. Here they are, and their associated XferCommand settings:
  
The {{ic|.pkg}} files ending in {{ic|.xz}} are simply tar'ed archives that can be decompressed with:
+
* {{ic|snarf}}: {{ic|1=XferCommand = /usr/bin/snarf -N %u}}
 +
* {{ic|lftp}}: {{ic|1=XferCommand = /usr/bin/lftp -c pget %u}}
 +
* {{ic|axel}}: {{ic|1=XferCommand = /usr/bin/axel -n 2 -v -a -o %o %u}}
 +
* {{ic|hget}}: {{ic|1=XferCommand = /usr/bin/hget %u -n 2 -skip-tls false}} (please read the [https://github.com/huydx/hget documentation on the Github project page] for more info)
  
$ tar xvf package.tar.xz
+
== Utilities ==
  
If you want to extract a couple of files out of a {{ic|.pkg}} file, this would be a way to do it.
+
* {{App|Lostfiles|Script that identifies files not owned by any package.|https://github.com/graysky2/lostfiles|{{Pkg|lostfiles}}}}
 +
* {{App|Pacmatic|''Pacman'' wrapper to check Arch News before upgrading, avoid partial upgrades, and warn about configuration file changes.|http://kmkeen.com/pacmatic|{{Pkg|pacmatic}}}}
 +
* {{App|pacutils|Helper library for libalpm based programs.|https://github.com/andrewgregory/pacutils|{{Pkg|pacutils}}}}
 +
* {{App|[[pkgfile]]|Tool that finds what package owns a file.|http://github.com/falconindy/pkgfile|{{Pkg|pkgfile}}}}
 +
* {{App|pkgtools|Collection of scripts for Arch Linux packages.|https://github.com/Daenyth/pkgtools|{{AUR|pkgtools}}}}
 +
* {{App|[[Powerpill]]|Uses parallel and segmented downloading through [[aria2]] and [[Reflector]] to try to speed up downloads for ''pacman''.|https://xyne.archlinux.ca/projects/powerpill/|{{AUR|powerpill}}}}
 +
* {{App|repoctl|Tool to help manage local repositories.|https://github.com/cassava/repoctl|{{AUR|repoctl}}}}
 +
* {{App|repose|An Arch Linux repository building tool.|https://github.com/vodik/repose|{{Pkg|repose}}}}
 +
* {{App|[[Snapper#Wrapping_pacman_transactions_in_snapshots|snap-pac]]|Make ''pacman'' automatically use snapper to create pre/post snapshots like openSUSE's YaST.|https://github.com/wesbarnett/snap-pac|{{pkg|snap-pac}}}}
 +
* {{App|vrms-arch|A virtual Richard M. Stallman to tell you which non-free packages are installed.|https://github.com/orospakr/vrms-arch|{{AUR|vrms-arch}}}}
  
=== Viewing a single file inside a .pkg file ===
+
=== Graphical ===
  
For example, if you want to see the contents of {{ic|/etc/conf.d/ntpd.conf}} supplied within the {{Pkg|ntp}} package:
+
{{Warning|PackageKit opens up system permissions by default, and is otherwise not recommended for general usage. See {{Bug|50459}} and {{Bug|57943}}.}}
  
$ tar -xOf /var/cache/pacman/pkg/ntp-4.2.6.p5-6-i686.pkg.tar.xz etc/conf.d/ntpd.conf
+
* {{App|Apper|Qt 5 application and package manager using PackageKit written in C++. Supports [https://www.freedesktop.org/wiki/Distributions/AppStream/ AppStream metadata].|https://userbase.kde.org/Apper|{{Pkg|apper}}}}
Or you can use vim, then browse the archive:
+
* {{App|Discover|Qt 5 application manager using PackageKit written in C++/QML. Supports [https://www.freedesktop.org/wiki/Distributions/AppStream/ AppStream metadata], [[Flatpak]] and [[fwupd|firmware updates]]. |https://userbase.kde.org/Discover|{{Pkg|discover}}}}
$ vim /var/cache/pacman/pkg/ntp-4.2.6.p5-6-i686.pkg.tar.xz
+
* {{App|GNOME PackageKit|GTK+ 3 package manager using PackageKit written in C.|https://freedesktop.org/software/PackageKit/|{{Pkg|gnome-packagekit}}}}
 +
* {{App|GNOME Software|GTK+ 3 application manager using PackageKit written in C. Supports [https://www.freedesktop.org/wiki/Distributions/AppStream/ AppStream metadata], [[Flatpak]] and [[fwupd|firmware updates]]. |https://wiki.gnome.org/Apps/Software|{{pkg|gnome-software}}}}
 +
* {{App|pcurses|Curses TUI pacman wrapper written in C++.|https://github.com/schuay/pcurses|{{Pkg|pcurses}}}}
 +
* {{App|tkPacman|Tk pacman wrapper written in Tcl.|https://sourceforge.net/projects/tkpacman|{{AUR|tkpacman}}}}

Latest revision as of 09:27, 8 December 2018

For general methods to improve the flexibility of the provided tips or pacman itself, see Core utilities and Bash.

Maintenance

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Usage= introduced with pacman 4.2, see [1] (Discuss in Talk:Pacman/Tips and tricks#)
Note: Instead of using comm (which requires sorted input with sort) in the sections below, you may also use grep -Fxf or grep -Fxvf.

See also System maintenance.

Listing packages

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 packages in the group named group: pacman -Sg group
  • List all explicitly installed native packages (i.e. present in the sync database) that are not direct or optional dependencies: pacman -Qent.
  • List all foreign packages (typically manually downloaded and installed or packages removed from the repositories): pacman -Qm.
  • List all native packages (installed from the sync database(s)): pacman -Qn.
  • List packages by regex: pacman -Qs regex.
  • List packages by regex with custom output format: expac -s "%-30n %v" regex (needs expac).

With size

Figuring out which packages are largest can be useful when trying to free space on your hard drive. There are two options here: get the size of individual packages, or get the size of packages and their dependencies.

Individual packages

The following command will list all installed packages and their individual sizes:

$ pacman -Qi | awk '/^Name/{name=$3} /^Installed Size/{print $4$5, name}' | sort -h
Packages and dependencies

To list package sizes with their dependencies,

  • Install expac and run expac -H M '%m\t%n' | sort -h.
  • Run pacgraph with the -c option.

To list the download size of several packages (leave packages blank to list all packages):

$ expac -S -H M '%k\t%n' packages

To list explicitly installed packages not in base nor base-devel with size and description:

$ expac -H M "%011m\t%-20n\t%10d" $(comm -23 <(pacman -Qqen | sort) <(pacman -Qqg base base-devel | sort)) | sort -n

To list the packages marked for upgrade with their download size

$ pacman -Quq|xargs expac -S -H M '%k\t%n' | sort -sh

By date

To list the 20 last installed packages with expac, run:

$ expac --timefmt='%Y-%m-%d %T' '%l\t%n' | sort | tail -n 20

or, with seconds since the epoch (1970-01-01 UTC):

$ expac --timefmt=%s '%l\t%n' | sort -n | tail -n 20

Not in a specified group or repository

Note: To get a list of packages installed as dependencies but no longer required by any installed package, see #Removing unused packages (orphans).

List explicitly installed packages not in the base or base-devel groups:

$ comm -23 <(pacman -Qeq | sort) <(pacman -Qgq base base-devel | sort)

List all installed packages unrequired by other packages, and which are not in the base or base-devel groups:

$ comm -23 <(pacman -Qqt | sort) <(pacman -Sqg base base-devel | sort)

As above, but with descriptions:

$ expac -HM '%-20n\t%10d' $(comm -23 <(pacman -Qqt | sort) <(pacman -Qqg base base-devel | sort))

List all installed packages that are not in the specified repository repo_name

$ comm -23 <(pacman -Qq | sort) <(pacman -Slq repo_name | sort)

List all installed packages that are in the repo_name repository:

$ comm -12 <(pacman -Qq | sort) <(pacman -Slq repo_name | sort)

List all packages on the Arch Linux ISO that are not in the base group:

$ comm -23 <(curl https://git.archlinux.org/archiso.git/plain/configs/releng/packages.both) <(pacman -Qqg base | sort)

Development packages

To list all development/unstable packages, run:

$ pacman -Qq | grep -Ee '-(bzr|cvs|darcs|git|hg|svn)$'

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

Identify files not owned by any package

If your system has stray files not owned by any package (a common case if you do not use the package manager to install software), you may want to find such files in order to clean them up.

One method is to use # pacreport --unowned-files from pacutils which will list unowned files among other details.

Another is to list all files of interest and check them against pacman:

# find /etc /usr /opt /var | LC_ALL=C pacman -Qqo - 2>&1 > /dev/null | cut -d ' ' -f 5-
Tip: The lostfiles script performs similar steps, but also includes an extensive blacklist to remove common false positives from the output.

Tracking unowned files created by packages

Most systems will slowly collect several ghost files such as state files, logs, indexes, etc. through the course of usual operation.

pacreport from pacutils can be used to track these files and their associations via /etc/pacreport.conf (see pacreport(1)).

An example may look something like this (abridged):

/etc/pacreport.conf
[Options]
IgnoreUnowned = usr/share/applications/mimeinfo.cache

[PkgIgnoreUnowned]
alsa-utils = var/lib/alsa/asound.state
bluez = var/lib/bluetooth
ca-certificates = etc/ca-certificates/trust-source/*
dbus = var/lib/dbus/machine-id
glibc = etc/ld.so.cache
grub = boot/grub/*
linux = boot/initramfs-linux.img
pacman = var/lib/pacman/local
update-mime-database = usr/share/mime/magic

Then, when using # pacreport --unowned-files, any unowned files will be listed if the associated package is no longer installed (or if any new files have been created).

Additionally, aconfmgr (aconfmgr-gitAUR) allows tracking modified and orphaned files using a configuration script.

Removing unused packages (orphans)

For recursively removing orphans and their configuration files:

# pacman -Rns $(pacman -Qtdq)

If no orphans were found pacman outputs error: no targets specified. This is expected as no arguments were passed to pacman -Rns.

Note: The arguments -Qt list only true orphans. To include packages which are optionally required by another package, pass the -t flag twice (i.e., -Qtt).

Removing everything but base group

If it is ever necessary to remove all packages except the base group, try this one-liner (requires pacman-contrib):

# pacman -R $(comm -23 <(pacman -Qq | sort) <((for i in $(pacman -Qqg base); do pactree -ul "$i"; done) | sort -u))

The one-liner was originally devised in this discussion, and later improved in this article.

Getting the dependencies list of several packages

Dependencies are alphabetically sorted and doubles are removed.

Note: To only show the tree of local installed packages, use pacman -Qi.
$ pacman -Si packages | awk -F'[:<=>]' '/^Depends/ {print $2}' | xargs -n1 | sort -u

Alternatively, with expac:

$ expac -l '\n' %E -S packages | sort -u

Listing changed backup 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. Modified backup files can be viewed with the following command:

# pacman -Qii | awk '/^MODIFIED/ {print $2}'

Running this command with root permissions will ensure that files readable only by root (such as /etc/sudoers) are included in the output.

Tip: See #Listing all changed files from packages to list all changed files pacman knows about, not only backup files.

Backup the pacman database

The following command can be used to backup the local pacman database:

$ tar -cjf pacman_database.tar.bz2 /var/lib/pacman/local

Store the backup pacman database file on one or more offline media, such as a USB stick, external hard drive, or CD-R.

The database can be restored by moving the pacman_database.tar.bz2 file into the / directory and executing the following command:

# tar -xjvf pacman_database.tar.bz2
Note: If the pacman database files are corrupted, and there is no backup file available, there exists some hope of rebuilding the pacman database. Consult #Restore pacman's local database.
Tip: The pakbak-gitAUR package provides a script and a systemd service to automate the task. Configuration is possible in /etc/pakbak.conf.

Check changelogs easily

When maintainers update packages, commits are often commented in a useful fashion. Users can quickly check these from the command line by installing pacologAUR. This utility lists recent commit messages for packages from the official repositories or the AUR, by using pacolog <package>.

Installation and recovery

Alternative ways of getting and restoring packages.

Installing packages from a CD/DVD or USB stick

Merge-arrows-2.pngThis article or section is a candidate for merging with #Custom local repository.Merge-arrows-2.png

Notes: Use as an example and avoid duplication (Discuss in Talk:Pacman/Tips and tricks#)

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 -Syu

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. 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/package-1.0-1-x86_64.pkg.tar.xz
Note: A package database is a tar file, optionally compressed. Valid extensions are .db or .files followed by an archive extension of .tar, .tar.gz, .tar.bz2, .tar.xz, or .tar.Z. The file does not need to exist, but all parent directories must exist.

The database and the packages do not need to be in the same directory when using repo-add, but keep in mind that when using pacman with that database, they should be together. Storing all the built packages to be included in the repository in one directory also allows to use shell glob expansion to add or update multiple packages at once:

$ repo-add /path/to/repo.db.tar.gz /path/to/*.pkg.tar.xz
Warning: repo-add adds the entries into the database in the same order as passed on the command line. If multiple versions of the same package are involved, care must be taken to ensure that the correct version is added last. In particular, note that lexical order used by the shell depends on the locale and differs from the vercmp ordering used by pacman.

repo-remove is used to remove packages from the package database, except that only package names are specified on the command line.

$ repo-remove /path/to/repo.db.tar.gz pkgname

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.

Network shared pacman cache

If you happen to run several Arch boxes on your LAN, you can share packages so that you can greatly decrease your download times. Keep in mind you should not share between different architectures (i.e. i686 and x86_64) or you will run into problems.

Read-only cache

If you are looking for a quick solution, you can simply run a standalone webserver which other computers can use as a first mirror:

# ln -s /var/lib/pacman/sync/*.db /var/cache/pacman/pkg
$ sudo -u http darkhttpd /var/cache/pacman/pkg --no-server-id

You could also run darkhttpd as a systemd service for convenience. Just add this server at the top of your /etc/pacman.d/mirrorlist in client machines with Server = http://mymirror:8080. Make sure to keep your mirror updated.

If you're already running a web server for some other purpose, you might wish to reuse that as your local repo server instead of darkhttpd. For example, say you already serve a site with nginx, you can add an nginx server block listening on port 8080:

/etc/nginx/nginx.conf
http {
    # ... other nginx server configs up here

    server {
        listen 8080;
        root /var/cache/pacman/pkg;
        server_name myarchrepo.localdomain;
        try_files $uri $uri/;
    }
}

Remember to restart nginx after making this change.

Whichever web server you use, remember to open port 8080 to local traffic (and you probably want to deny anything not local), so add a rule like the following to iptables:

/etc/iptables/iptables.rules
-A TCP -s 192.168.0.0/16 -p tcp -m tcp --dport 8080 -j ACCEPT

Remember to restart iptables after making this change.

Distributed read-only cache

There are Arch-specific tools for automatically discovering other computers on your network offering a package cache. Try pacredir, pacserve, pkgdistcacheAUR, or paclanAUR. pkgdistcache uses Avahi instead of plain UDP which may work better in certain home networks that route instead of bridge between WiFi and Ethernet.

Historically, there was PkgD and multipkg, but they are no longer maintained.

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 packages: shfs-utils, sshfs, curlftpfs, samba or nfs-utils.

Tip:
  • To use sshfs or shfs, consider reading Using SSH Keys.
  • By default, smbfs does not serve filenames that contain colons, which results in the client downloading the offending package afresh. To prevent this, use the mapchars mount option on the client.

Then, to share the actual packages, mount /var/cache/pacman/pkg from the server to /var/cache/pacman/pkg on every client machine.

Warning: Do not make /var/cache/pacman/pkg or any of its ancestors (e.g., /var) a symlink. Pacman expects these to be directories. When pacman re-installs or upgrades itself, it will remove the symlinks and create empty directories instead. However during the transaction pacman relies on some files residing there, hence breaking the update process. Refer to FS#50298 for further details.

two-way with rsync

Another approach in a local environment is rsync. Choose a server for caching and enable the Rsync#rsync daemon. On clients synchronize two-way with this share via rsync protocol. Filenames that contain colons are no problem for the rsync protocol.

Draft example for a client, using uname -m within the share name ensures an architecture dependant sync:

 # rsync rsync://server/share_$(uname -m)/ /var/cache/pacman/pkg/ ...
 # pacman ...
 # paccache ...
 # rsync /var/cache/pacman/pkg/ rsync://server/share_$(uname -m)/  ...

Dynamic reverse proxy cache using nginx

nginx can be used to proxy requests to official upstream mirrors and cache the results to local disk. All subsequent requests for that file will be served directly from the local cache, minimizing the amount of internet traffic needed to update a large number of servers with minimal effort.

Warning: This method has a limitation. You must use mirrors that use the same relative path to package files and you must configure your cache to use that same path. In this example, we are using mirrors that use the relative path /archlinux/$repo/os/$arch and our cache's Server setting in mirrorlist is configured similarly.

In this example, we will run the cache server on http://cache.domain.example:8080/ and storing the packages in /srv/http/pacman-cache/.

Create the directory for the cache and adjust the permissions so nginx can write files to it:

 # mkdir /srv/http/pacman-cache
 # chown http:http /srv/http/pacman-cache

Next, configure nginx as the dynamic cache (read the comments for an explanation of the commands).

Finally, update your other Arch Linux servers to use this new cache by adding the following line to the mirrorlist file:

/etc/pacman.d/mirrorlist
Server = http://cache.domain.example:8080/archlinux/$repo/os/$arch
...
Note: You will need to create a method to clear old packages, as this directory will continue to grow over time. paccache (which is provided by pacman-contrib) can be used to automate this using retention criteria of your choosing. For example, find /srv/http/pacman-cache/ -type d -exec paccache -v -r -k 2 -c {} \; will keep the last 2 versions of packages in your cache directory.

Synchronize pacman package cache using synchronization programs

Use Syncthing or Resilio Sync to synchronize the pacman cache folders (i.e. /var/cache/pacman/pkg).

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 fakepkgAUR. 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 Linux Archive for alternatives.

List of installed packages

Keeping a list of all the explicitly installed packages can be useful, to backup a system for example or speed up installation on a new system:

$ pacman -Qqe > pkglist.txt
Note:
  • With option -t, the packages already required by other explicitly installed packages are not mentioned. If reinstalling from this list they will be installed but as dependencies only.
  • With option -n, foreign packages (e.g. from AUR) would be omitted from the list.
  • Use comm -13 <(pacman -Qqdt | sort) < (pacman -Qqdtt | sort) > optdeplist.txt to also create a list of the installed optional dependencies which can be reinstalled with --asdeps.
  • Use pacman -Qqem > foreignpkglist.txt to create the list of AUR and other foreign packages that have been explicitly installed.

To keep an up-to-date list of explicitly installed packages (e.g. in combination with a versioned /etc/), you can set up a hook. Example:

[Trigger]
Operation = Install
Operation = Remove
Type = Package
Target = *

[Action]
When = PostTransaction
Exec = /bin/sh -c '/usr/bin/pacman -Qqe > /etc/pkglist.txt'

Install packages from a list

To install packages from a previously saved list of packages, while not reinstalling previously installed packages that are already up-to-date, run:

# pacman -S --needed - < pkglist.txt

However, it is likely foreign packages such as from the AUR or installed locally are present in the list. To filter out from the list the foreign packages, the previous command line can be enriched as follows:

# pacman -S --needed $(comm -12 <(pacman -Slq | sort) <(sort pkglist.txt))

Eventually, to make sure the installed packages of your system match the list and remove all the packages that are not mentioned in it:

# pacman -Rsu $(comm -23 <(pacman -Qq | sort) <(sort pkglist.txt))
Tip: These tasks can be automated. See bacpacAUR, packupAUR, pacmanityAUR, and pugAUR for examples.

Listing all changed files from packages

If you are suspecting file corruption (e.g. by software/hardware failure), but are unsure if files were corrupted, you might want to compare with the hash sums in the packages. This can be done with pacutils:

# paccheck --md5sum --quiet

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.

Note: This should not be used as is when suspecting malicious changes! In this case security precautions such as using a live medium and an independent source for the hash sums are advised.

Reinstalling all packages

To reinstall all native packages, use:

# pacman -Qqn | pacman -S -

Foreign (AUR) packages must be reinstalled separately; you can list them with pacman -Qqm.

Pacman preserves the installation reason by default.

Restore pacman's local database

See Pacman/Restore local database.

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

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 to 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.

Performance

Download speeds

Note: If your download speeds have been reduced to a crawl, ensure you are using one of the many mirrors and not ftp.archlinux.org, which is throttled since March 2007.

When downloading packages pacman uses the mirrors in the order they are in /etc/pacman.d/mirrorlist. The mirror which is at the top of the list by default however may not be the fastest for you. To select a faster mirror, see Mirrors.

Pacman's speed in downloading packages can also be improved by using a different application to download packages, instead of pacman's built-in file downloader.

In all cases, make sure you have the latest pacman before doing any modifications.

# pacman -Syu

Powerpill

Powerpill is a pacman wrapper that uses parallel and segmented downloading to try to speed up downloads for pacman.

wget

This is also very handy if you need more powerful proxy settings than pacman's built-in capabilities.

To use wget, first install the wget package then modify /etc/pacman.conf by uncommenting the following line in the [options] section:

XferCommand = /usr/bin/wget --passive-ftp -c -O %o %u

Instead of uncommenting the wget parameters in /etc/pacman.conf, you can also modify the wget configuration file directly (the system-wide file is /etc/wgetrc, per user files are $HOME/.wgetrc.

aria2

aria2 is a lightweight download utility with support for resumable and segmented HTTP/HTTPS and FTP downloads. aria2 allows for multiple and simultaneous HTTP/HTTPS and FTP connections to an Arch mirror, which should result in an increase in download speeds for both file and package retrieval.

Note: Using aria2c in pacman's XferCommand will not result in parallel downloads of multiple packages. Pacman invokes the XferCommand with a single package at a time and waits for it to complete before invoking the next. To download multiple packages in parallel, see Powerpill.

Install aria2, then edit /etc/pacman.conf by adding the following line to the [options] section:

XferCommand = /usr/bin/aria2c --allow-overwrite=true --continue=true --file-allocation=none --log-level=error --max-tries=2 --max-connection-per-server=2 --max-file-not-found=5 --min-split-size=5M --no-conf --remote-time=true --summary-interval=60 --timeout=5 --dir=/ --out %o %u
Tip: This alternative configuration for using pacman with aria2 tries to simplify configuration and adds more configuration options.

See OPTIONS in aria2c(1) for used aria2c options.

  • -d, --dir: The directory to store the downloaded file(s) as specified by pacman.
  • -o, --out: The output file name(s) of the downloaded file(s).
  • %o: Variable which represents the local filename(s) as specified by pacman.
  • %u: Variable which represents the download URL as specified by pacman.

Other applications

There are other downloading applications that you can use with pacman. Here they are, and their associated XferCommand settings:

  • snarf: XferCommand = /usr/bin/snarf -N %u
  • lftp: XferCommand = /usr/bin/lftp -c pget %u
  • axel: XferCommand = /usr/bin/axel -n 2 -v -a -o %o %u
  • hget: XferCommand = /usr/bin/hget %u -n 2 -skip-tls false (please read the documentation on the Github project page for more info)

Utilities

  • Lostfiles — Script that identifies files not owned by any package.
https://github.com/graysky2/lostfiles || lostfiles
  • PacmaticPacman wrapper to check Arch News before upgrading, avoid partial upgrades, and warn about configuration file changes.
http://kmkeen.com/pacmatic || pacmatic
  • pacutils — Helper library for libalpm based programs.
https://github.com/andrewgregory/pacutils || pacutils
  • pkgfile — Tool that finds what package owns a file.
http://github.com/falconindy/pkgfile || pkgfile
  • pkgtools — Collection of scripts for Arch Linux packages.
https://github.com/Daenyth/pkgtools || pkgtoolsAUR
  • Powerpill — Uses parallel and segmented downloading through aria2 and Reflector to try to speed up downloads for pacman.
https://xyne.archlinux.ca/projects/powerpill/ || powerpillAUR
  • repoctl — Tool to help manage local repositories.
https://github.com/cassava/repoctl || repoctlAUR
  • repose — An Arch Linux repository building tool.
https://github.com/vodik/repose || repose
  • snap-pac — Make pacman automatically use snapper to create pre/post snapshots like openSUSE's YaST.
https://github.com/wesbarnett/snap-pac || snap-pac
  • vrms-arch — A virtual Richard M. Stallman to tell you which non-free packages are installed.
https://github.com/orospakr/vrms-arch || vrms-archAUR

Graphical

Warning: PackageKit opens up system permissions by default, and is otherwise not recommended for general usage. See FS#50459 and FS#57943.
  • Apper — Qt 5 application and package manager using PackageKit written in C++. Supports AppStream metadata.
https://userbase.kde.org/Apper || apper
https://userbase.kde.org/Discover || discover
  • GNOME PackageKit — GTK+ 3 package manager using PackageKit written in C.
https://freedesktop.org/software/PackageKit/ || gnome-packagekit
https://wiki.gnome.org/Apps/Software || gnome-software
  • pcurses — Curses TUI pacman wrapper written in C++.
https://github.com/schuay/pcurses || pcurses
  • tkPacman — Tk pacman wrapper written in Tcl.
https://sourceforge.net/projects/tkpacman || tkpacmanAUR