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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]]
[[ja:Pacman Tips]]
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[[fr:Astuces Pacman]]
[[ru:Pacman Tips]]
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[[it:Pacman/Tips and tricks]]
[[tr:Pacman_ipuçları]]
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[[ja:Pacman ヒント]]
[[zh-CN:Pacman Tips]]
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[[pt:Pacman/Tips and tricks]]
{{Article summary start|Summary}}
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[[ru:Pacman/Tips and tricks]]
{{Article summary text|This is a collection of common tips for new pacman users.}}
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[[zh-hans:Pacman/Tips and tricks]]
{{Article summary heading|Related}}
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{{Related articles start}}
{{Article summary wiki|pacman}}
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{{Related|Mirrors}}
{{Article summary wiki|Mirrors}}
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{{Related|Creating packages}}
{{Article summary wiki|Creating Packages}}
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{{Related articles end}}
{{Article summary wiki|Custom local repository}}
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For general methods to improve the flexibility of the provided tips or ''pacman'' itself, see [[Core utilities]] and [[Bash]].
{{Article summary end}}
 
  
== Cosmetic and Convienence ==
+
== Maintenance ==
  
=== Color output ===
+
{{Expansion|{{ic|1=Usage=}} introduced with pacman 4.2, see [http://allanmcrae.com/2014/12/pacman-4-2-released/]}}
  
As of version 4.1, Pacman has a color option. Uncomment the "Color" line in {{ic|pacman.conf}}.
+
{{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}}.}}
  
=== Shortcuts ===
+
See also [[System maintenance]].
  
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.
+
=== Listing packages ===
  
==== Configure the shell ====
+
You may want to get the list of installed packages with their version, which is useful when reporting bugs or discussing installed packages.
  
Add the following examples, which work in both [[Bash]] and [[Zsh]]:
+
* List all explicitly installed packages: {{ic|pacman -Qe}}.
{{bc|<nowiki> # Pacman alias examples
+
* List all explicitly installed native packages (i.e. present in the sync database) that are not direct or optional dependencies: {{ic|pacman -Qent}}.
alias pacupg='sudo pacman -Syu'        # Synchronize with repositories and then upgrade packages that are out of date on the local system.
+
* List all foreign packages (typically manually downloaded and installed): {{ic|pacman -Qm}}.
alias pacin='sudo pacman -S'          # Install specific package(s) from the repositories
+
* List all native packages (installed from the sync database(s)): {{ic|pacman -Qn}}.
alias pacins='sudo pacman -U'          # Install specific package not from the repositories but from a file
+
* List packages by regex: {{ic|pacman -Qs ''regex''}}.
alias pacre='sudo pacman -R'          # Remove the specified package(s), retaining its configuration(s) and required dependencies
+
* List packages by regex with custom output format: {{ic|expac -s "%-30n %v" ''regex''}} (needs {{Pkg|expac}}).
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
+
==== With size ====
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 ====
+
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.
  
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:
+
===== Individual packages =====
$ 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 following command will list all installed packages and their individual sizes:
  
The aliases used above are merely examples. By following the syntax samples above, rename the aliases as convenient. For example:
+
$ pacman -Qi | awk '/^Name/{name=$3} /^Installed Size/{print $4$5, name}' | sort -h
  
alias pacrem='sudo pacman -Rns'
+
===== Packages and 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.
+
To list package sizes with their dependencies,
  
=== Operations and Bash syntax ===
+
* Install {{Pkg|expac}} and run {{ic|<nowiki>expac -H M '%m\t%n' | sort -h</nowiki>}}.
 +
* Run {{Pkg|pacgraph}} with the {{ic|-c}} option.
  
In addition to pacman's standard set of features, there are ways to extend its usability through rudimentary [[Bash]] commands/syntax.
+
To list the download size of several packages (leave {{ic|''packages''}} blank to list all packages):
  
* To install a number of packages sharing similar patterns in their names -- not the entire group nor all matching packages; eg. {{Pkg|kde}}:
+
$ expac -S -H M '%k\t%n' ''packages''
  
# pacman -S kde-{applets,theme,tools}
+
To list explicitly installed packages not in {{Grp|base}} nor {{Grp|base-devel}} with size and description:
  
* Of course, that is not limited and can be expanded to however many levels needed:
+
$ expac -H M "%011m\t%-20n\t%10d" $(comm -23 <(pacman -Qqen | sort) <(pacman -Qqg base base-devel | sort)) | sort -n
  
# pacman -S kde-{ui-{kde,kdemod},kdeartwork}
+
==== By date ====
  
* 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:
+
To list the 20 last installed packages with {{Pkg|expac}}, run:
  
  # pacman -Ss '^vim-'
+
  $ expac --timefmt='%Y-%m-%d %T' '%l\t%n' | sort | tail -n 20
  
* 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:
+
or, with seconds since the epoch (1970-01-01 UTC):
  
  # pacman -S $(pacman -Qq | grep compiz)
+
  $ expac --timefmt=%s '%l\t%n' | sort -n | tail -n 20
  
* Or install all packages available in a repository (kde-unstable for example):
+
==== Not in a specified group or repository ====
  
# pacman -S $(pacman -Slq kde-unstable)
+
{{Note|To get a list of packages installed as dependencies but no longer required by any installed package, see [[#Removing unused packages (orphans)]].}}
  
== Maintenance ==
+
List explicitly installed packages not in the {{Grp|base}} or {{Grp|base-devel}} groups:
  
''House keeping, in the interest of keeping a clean system and following [[The Arch Way]]''
+
$ comm -23 <(pacman -Qeq | sort) <(pacman -Qgq base base-devel | sort)
  
=== Listing all installed packages with size ===
+
List all installed packages unrequired by other packages, and which are not in the {{Grp|base}} or {{Grp|base-devel}} groups:
  
* You may want to get the list of installed packages sorted by size, which may be useful when freeing space on your hard drive.
+
$ comm -23 <(pacman -Qqt | sort) <(pacman -Sqg base base-devel | sort)
* Use {{ic|pacsysclean}} from {{Pkg|pacman}} package.
 
* Install {{Pkg|expac}} and run {{ic| <nowiki>expac -s "%-30n %m" | sort -rhk 2</nowiki>}}
 
* Invoke pacgraph with the -c option to produce a list of all installed packages with their respective sizes on the system.  {{Pkg|pacgraph}} is available from [community].
 
* {{ic|<nowiki>pacman -Qi | egrep "Name|Installed Size" | sed -e 'N;s/\n/ /' | awk '{ print $7, $3}' | sort -n</nowiki>}} (note that some packages with "Name" in their descriptions will disrupt this (e.g. {{Pkg|idnkit}}))
 
  
=== Listing installed packages with version ===
+
As above, but with descriptions:
  
* You may want to get the list of installed packages with their version, which is useful when reporting bugs or discussing installed packages.
+
$ expac -HM '%-20n\t%10d' $(comm -23 <(pacman -Qqt | sort) <(pacman -Qqg base base-devel | sort))
* List all explicitly installed packages: {{ic| pacman -Qe }}.
 
* List all foreign packages (typically manually downloaded and installed): {{ic| pacman -Qm }}.
 
* List all native packages (installed from the sync database(s)): {{ic| pacman -Qn }}.
 
* List packages by regex: {{ic| <nowiki>pacman -Qs <regex> | awk 'BEGIN { RS="\n" ; FS="/" } { print $2 }' | awk '{ if(NF > 0) print $1, $2 }'</nowiki>}}
 
* Install {{Pkg|expac}} and run {{ic| expac -s "%-30n %v"}}
 
  
=== Identify files not owned by any package ===
+
List all installed packages that are ''not'' in the specified repository ''repo_name''
  
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:
+
$ comm -23 <(pacman -Qq | sort) <(pacman -Slq ''repo_name'' | sort)
  
{{hc|pacman-disowned|<nowiki>
+
List all installed packages that are in the ''repo_name'' repository:
#!/bin/sh
 
  
tmp=${TMPDIR-/tmp}/pacman-disowned-$UID-$$
+
$ comm -12 <(pacman -Qq | sort) <(pacman -Slq ''repo_name'' | sort)
db=$tmp/db
 
fs=$tmp/fs
 
  
mkdir "$tmp"
+
List all packages on the Arch Linux ISO that are not in the base group:
trap 'rm -rf "$tmp"' EXIT
 
  
pacman -Qlq | sort -u > "$db"
+
<nowiki>$ comm -23 <(curl https://git.archlinux.org/archiso.git/plain/configs/releng/packages.both) <(pacman -Qqg base | sort)</nowiki>
  
find /bin /etc /sbin /usr \
+
==== Development packages ====
  ! -name lost+found \
 
  \( -type d -printf '%p/\n' -o -print \) | sort > "$fs"
 
  
comm -23 "$fs" "$db"</nowiki>}}
+
To list all development/unstable packages, run:
  
To generate the list:
+
$ pacman -Qq | grep -Ee '-(cvs|svn|git|hg|bzr|darcs)$'
  
$ pacman-disowned > non-db.txt
+
=== Listing files owned by a package with size ===
  
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}}.
+
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.
  
=== Removing orphaned packages ===
+
$ pacman -Qlq ''package'' | grep -v '/$' | xargs du -h | sort -h
  
For ''recursively'' removing orphans:
+
=== Identify files not owned by any package ===
  
{{bc|# pacman -Rs $(pacman -Qtdq)}}
+
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. The general process for doing so is:
  
The following '''alias''' is easily inserted into {{ic|~/.bashrc}} and removes orphans if found:
+
# Create a sorted list of the files you want to check ownership of: {{bc|<nowiki>$ find /etc /opt /usr | sort > all_files.txt</nowiki>}}
 +
# Create a sorted list of the files tracked by ''pacman'' (and remove the trailing slashes from directories): {{bc|<nowiki>$ pacman -Qlq | sed 's|/$||' | sort > owned_files.txt</nowiki>}}
 +
# Find lines in the first list that are not in the second: {{bc|$ comm -23 all_files.txt owned_files.txt}}
  
{{hc|~/.bashrc|<nowiki># '[r]emove [o]rphans' - recursively remove ALL orphaned packages
+
This process is tricky in practice because many important files are not part of any package (e.g. files generated at runtime, custom configs) and so will be included in the final output, making it difficult to pick out the files that can be safely deleted.
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:
+
{{Tip|The {{Pkg|lostfiles}} script performs similar steps, but also includes an extensive blacklist to remove common false positives from the output. [https://github.com/CyberShadow/aconfmgr aconfmgr] ({{AUR|aconfmgr-git}}) also allows tracking orphaned files using a configuration script.}}
  
{{hc|~/.bashrc|<nowiki>
+
=== Removing unused packages (orphans) ===
orphans() {
 
  if [[ ! -n $(pacman -Qdt) ]]; then
 
    echo "No orphans to remove."
 
  else
 
    sudo pacman -Rs $(pacman -Qdtq)
 
  fi
 
}</nowiki>}}
 
  
=== Removing everything but base group ===
+
For recursively removing orphans and their configuration files:
  
If it is ever necessary to remove all packages except the base group, try this one liner:
+
# pacman -Rns $(pacman -Qtdq)
  
# pacman -Rs $(comm -23 <(pacman -Qeq|sort) <((for i in $(pacman -Qqg base); do pactree -ul $i; done)|sort -u|cut -d ' ' -f 1))
+
If no orphans were found ''pacman'' outputs {{ic|error: no targets specified}}. This is expected as no arguments were passed to {{ic|pacman -Rns}}.
  
Source: [https://bbs.archlinux.org/viewtopic.php?id=130176 Look at discussion here]
+
{{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}}).}}
  
Notes:
+
=== Removing everything but base group ===
  
# {{ic|comm}} requires sorted input otherwise you get e.g. {{ic|comm: file 1 is not in sorted order}}.
+
If it is ever necessary to remove all packages except the base group, try this one-liner (requires {{Pkg|pacman-contrib}}):
# {{ic|pactree}} prints the package name followed by what it provides. For example:
 
  
{{hc|$ pactree -lu logrotate|
+
# pacman -R $(comm -23 <(pacman -Qq | sort) <((for i in $(pacman -Qqg base); do pactree -ul "$i"; done) | sort -u))
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.
+
The one-liner was originally devised in [https://bbs.archlinux.org/viewtopic.php?id=130176 this discussion], and later improved in this article.
 
 
=== 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 ===
 
=== Getting the dependencies list of several packages ===
  
 
Dependencies are alphabetically sorted and doubles are removed.
 
Dependencies are alphabetically sorted and doubles are removed.
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
+
{{Note|To only show the tree of local installed packages, use {{ic|pacman -Qi}}.}}
  
Alternatively, you can use {{ic|expac}}: {{ic|expac -l '\n' %E -S $@ &#124; sort -u}}.
+
$ pacman -Si ''packages'' | awk -F'[:<=>]' '/^Depends/ {print $2}' | xargs -n1 | sort -u
  
=== Getting the size of several packages ===
+
Alternatively, with {{Pkg|expac}}:
  
You can use (and tweak) this little shell function:
+
$ expac -l '\n' %E -S ''packages'' | sort -u
  
{{hc|~/.bashrc|<nowiki>
+
=== Listing changed backup files ===
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
+
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:
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 {{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}'
 
  # 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 ===
 
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>
 
#!/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=""
 
 
# Temporary file locations
 
tmpdir=/tmp
 
ignored=$tmpdir/ignored
 
installed=$tmpdir/installed
 
 
# Generate list of installed packages and packages you wish to keep.
 
echo $(pacman -Sg $ignoregrp | awk '{print $2}') $ignorepkg | tr ' ' '\n' | sort | uniq > $ignored
 
pacman -Qq | sort > $installed
 
 
# Do not loop packages you are keeping
 
loop=$(comm -13 $ignored $installed)
 
 
# Check each remaining package. If package is not required by anything and
 
# 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
 
rm $ignored $installed
 
</nowiki>}}
 
  
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.
+
Running this command with root permissions will ensure that files readable only by root (such as {{ic|/etc/sudoers}}) are included in the output.
  
The following script has the option to exclude files like above, but uses expac:
+
{{Tip|See [[#Listing all changed files from packages]] to list all changed files ''pacman'' knows, not only backup files.}}
  
{{hc|clean|<nowiki>
+
=== Back-up the pacman database ===
#!/bin/bash
 
  
# Generate list of installed packages (leaves in package dependency tree).
+
The following command can be used to back up the local ''pacman'' database:
# Give it a list with packages that should be ignored in the final list, each
 
# package on a separate line.
 
  
# Temporary files
+
$ tar -cjf pacman_database.tar.bz2 /var/lib/pacman/local
IGNORED=$(mktemp)
 
[ -n "$1" ] && cat "$1" >$IGNORED
 
LIST="$(mktemp)"
 
  
expac "%n %N" -Q $(expac "%n %G" | grep -v ' base') | awk '$2 == "" {print $1}' > "$LIST"
+
Store the backup ''pacman'' database file on one or more offline media, such as a USB stick, external hard drive, or CD-R.
  
# Sort both lists, so they can be diffed.
+
The database can be restored by moving the {{ic|pacman_database.tar.bz2}} file into the {{ic|/}} directory and executing the following command:
TMPF=$(mktemp)
 
sort "$IGNORED" | grep -v '^$' > "$TMPF"
 
sort -o "$LIST" "$LIST"
 
IGNORED="$TMPF"
 
# Diff the lists.
 
comm -13 "$IGNORED" "$LIST"
 
</nowiki>}}
 
  
=== Backing up Local database with Systemd ===
+
# tar -xjvf pacman_database.tar.bz2
  
[https://wiki.archlinux.org/index.php/Systemd Systemd] can take snapshots of the pacman local database everytime it is modified.
+
{{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]].}}
  
{{Note| There is a more configurable version in the AUR: {{AUR|pakbak-git}}}}
+
{{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}}.}}
{{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
+
=== Check changelogs easily ===
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}}.}}
+
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>
 
[Unit]
 
Description=Back up pacman database
 
 
 
[Service]
 
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}}.}}
 
{{bc|<nowiki>
 
[Unit]
 
Description=Back up pacman database
 
 
 
[Path]
 
PathChanged=/var/lib/pacman/local
 
Unit=pakbak.service
 
 
 
[Install]
 
WantedBy=multi-user.target
 
</nowiki>}}
 
 
 
{{Tip|To start the backup service :
 
{{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 389: Line 205:
 
  # 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.
 +
 
 +
==== 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.
 +
 
 +
{{Note|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.}}
 +
 
 +
==== 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 {{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)/  ...
 +
 
 +
==== 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 {{ic|/archlinux/$repo/os/$arch}} and our cache's {{ic|Server}} setting in {{ic|mirrorlist}} is configured similarly.}}
 +
 
 +
In this example, we will run the cache server on {{ic|<nowiki>http://cache.domain.local:8080/</nowiki>}} and storing the packages in {{ic|/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 [https://gist.github.com/anonymous/97ec4148f643de925e433bed3dc7ee7d dynamic cache] (read the comments for an explanation of the commands).
  
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.
+
Finally, update your other Arch Linux servers to use this new cache by adding the following line to the {{ic|mirrorlist}} file:
  
First, install any network-supporting filesystem; for example [[sshfs]], [[shfs]], ftpfs, [[smbfs]] or [[nfs]].
+
{{hc|/etc/pacman.d/mirrorlist|<nowiki>
 +
Server = http://cache.domain.local:8080/archlinux/$repo/os/$arch
 +
...
 +
</nowiki>}}
  
{{Tip|To use sshfs or shfs, consider reading [[Using SSH Keys]].}}
+
{{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.}}
  
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.
+
==== Synchronize pacman package cache using synchronization programs ====
  
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}}.
+
Use [[Resilio Sync]] or [[Syncthing]] to synchronize the ''pacman'' cache folders (i.e. {{ic|/var/cache/pacman/pkg}}).
  
 
==== Preventing unwanted cache purges ====
 
==== Preventing unwanted cache purges ====
  
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.
+
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.
  
 
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}}:
 
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}}:
Line 448: Line 316:
 
  CleanMethod = KeepCurrent
 
  CleanMethod = KeepCurrent
  
=== Backing up and retrieving a list of installed packages ===
+
=== 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 Linux Archive]] for alternatives.
 +
 
 +
{{Tip|''bacman'' honours the {{ic|PACKAGER}}, {{ic|PKGDEST}} and {{ic|PKGEXT}} options from {{ic|makepkg.conf}}. Bacman does not currently honor the {{ic|COMPRESS}} options in {{ic|makepkg.conf}}.}}
  
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.
+
An alternative tool would be {{AUR|fakepkg}}. It supports parallelization and can handle multiple input packages in one command, which ''bacman'' both does not support.
  
* First, backup the current list of non-local packages:
+
=== List of installed packages ===
  
: $ pacman -Qqen > pkglist.txt
+
Keeping a list of explicitly installed packages can be useful to speed up installation on a new system:
  
* Store the {{ic|pkglist.txt}} on a USB key or other convenient medium or gist.github.com or Evernote, Dropbox, etc.
+
$ pacman -Qqe > pkglist.txt
  
* Copy the {{ic|pkglist.txt}} file to the new installation, and navigate to the directory containing it.
+
{{Note|If the option {{ic|-t}} was used, when reinstalling the list all the non-top-level packages would be set as dependencies. With option {{ic|-n}}, foreign packages (e.g. from AUR) would be omitted from the list.}}
  
* Issue the following command to install from the backup list:
+
To install packages from the list backup, run:
  
: # pacman -S $(< pkglist.txt)
+
# 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).
+
{{Tip|
 +
* To skip already installed packages, use {{ic|--needed}}.
 +
* Use {{ic|<nowiki>comm -13 <(pacman -Qqdt | sort) <(pacman -Qqdtt | sort) > optdeplist.txt</nowiki>}} to also create a list of the installed optional dependencies which can be reinstalled with {{ic|--asdeps}}.
 +
}}
  
In such a case, you may still want to install all available packages from that list:
+
In case the list includes foreign packages, such as [[AUR]] packages, remove them first:
  
  # pacman -S --needed $(comm -12 <(pacman -Slq|sort) <(sort badpkdlist) )
+
  # pacman -S $(comm -12 <(pacman -Slq | sort) <(sort pkglist.txt))
  
Explanation:
+
To remove all the packages on your system that are not mentioned in the list:
  
* {{ic|pacman -Slq}} lists all available softwares, but the list is sorted by repository first, hence the {{ic|sort}} command.
+
# pacman -Rsu $(comm -23 <(pacman -Qq | sort) <(sort pkglist.txt))
* 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):
+
{{Tip|These tasks can be automated. See {{AUR|bacpac}}, {{AUR|packup}}, {{AUR|pacmanity}}, and {{AUR|pug}} for examples.}}
  
$ yaourt -S --needed $(comm -13 <(pacman -Slq|sort) <(sort badpkdlist) )
+
If you would like 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:
  
Finally, you may want to remove all the packages on your system that are not mentioned in the list.
+
[Trigger]
 +
Operation = Install
 +
Operation = Remove
 +
Type = Package
 +
Target = *
 +
 +
[Action]
 +
When = PostTransaction
 +
Exec = /bin/sh -c '/usr/bin/pacman -Qqe > /etc/packages.txt'
  
{{Warning|Use this command wisely, and always check the result prompted by pacman.}}
+
=== Listing all changed files from packages ===
  
# pacman -Rsu $(comm -23 <(pacman -Qq|sort) <(sort pkglist))
+
If you are suspecting file corruption (e.g. by software/hardware failure), but are unsure if files were got corrupted, you might want to compare with the hash sums in the packages. This can be done with {{Pkg|pacutils}}:
  
=== List downloaded packages that are not in base or base-devel ===
+
# paccheck --md5sum --quiet
  
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:
+
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]].
  
$ comm -23 <(pacman -Qeq|sort) <(pacman -Qgq base base-devel|sort)
+
{{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 ===
 
=== Reinstalling all packages ===
 
To reinstall all native packages, use:
 
To reinstall all native packages, use:
  
  # pacman -Qenq | pacman -S -
+
  # pacman -Qnq | pacman -S -
  
Foreign (AUR) packages must be reinstalled separately; you can list them with {{ic|pacman -Qemq}}.
+
Foreign (AUR) packages must be reinstalled separately; you can list them with {{ic|pacman -Qmq}}.
  
Pacman preserves the installation reason by default.
+
''Pacman'' preserves the [[installation reason]] by default.
  
 
=== Restore pacman's local database ===
 
=== Restore pacman's local database ===
  
Signs that pacman needs a local database restoration:
+
See [[Pacman/Restore local database]].
  
* {{ic|pacman -Q}} gives absolutely no output, and {{Ic|pacman -Syu}} erroneously reports that the system is up to date.
+
=== Recovering a USB key from existing install ===
* When trying to install a package using {{ic|pacman -S package}}, and it outputs a list of already satisfied dependencies.
 
* 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.
+
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}})
  
Firstly, make sure pacman's log file is present:
+
# pacman -S $(pacman -Qq --dbpath /newarch/var/lib/pacman) --root /newarch --dbpath /newarch/var/lib/pacman
  
$ ls /var/log/pacman.log
+
=== Viewing a single file inside a .pkg file ===
  
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.
+
For example, if you want to see the contents of {{ic|/etc/systemd/logind.conf}} supplied within the {{Pkg|systemd}} package:
  
==== Log filter script ====
+
$ tar -xOf /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz etc/systemd/logind.conf
{{hc|pacrecover|<nowiki>
 
#!/bin/bash -e
 
  
. /etc/makepkg.conf
+
Or you can use {{pkg|vim}} to browse the archive:
  
PKGCACHE=$((grep -m 1 '^CacheDir' /etc/pacman.conf || echo 'CacheDir = /var/cache/pacman/pkg') | sed 's/CacheDir = //')
+
$ vim /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz
  
pkgdirs=("$@" "$PKGDEST" "$PKGCACHE")
+
=== Find applications that use libraries from older packages ===
  
while read -r -a parampart; do
+
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.
  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
+
Here is a way how to find all the programs that use old packages code:
  
==== Generating the package recovery list ====
+
# 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.
  
{{Warning|If for some reason your [[pacman]] cache or [[makepkg]] package destination contain packages for other architectures, remove them before continuation.}}
+
== Performance ==
  
Run the script (optionally passing additional directories with packages as parameters):
+
=== Download speeds ===
  
$ paclog-pkglist /var/log/pacman.log | ./pacrecover >files.list 2>pkglist.orig
+
{{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].}}
  
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.
+
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]].
  
Here is a way to automatically restrict second list to packages available in a repository:
+
''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.
  
$ { cat pkglist.orig; pacman -Slq; } | sort | uniq -d > pkglist
+
In all cases, make sure you have the latest ''pacman'' before doing any modifications.
  
Check if some important ''base'' package are missing, and add them to the list:
+
# pacman -Syu
  
$ comm -23 <(pacman -Sgq base) pkglist.orig >> pkglist
+
==== Powerpill ====
  
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/}}.
+
[[Powerpill]] is a ''pacman'' wrapper that uses parallel and segmented downloading to try to speed up downloads for ''pacman''.
  
==== Performing the recovery ====
+
==== wget ====
  
Define bash alias for recovery purposes:
+
This is also very handy if you need more powerful proxy settings than ''pacman''<nowiki>'</nowiki>s built-in capabilities.
  
# recovery-pacman() {
+
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:
    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.
+
XferCommand = /usr/bin/wget --passive-ftp -c -O %o %u
  
Populate the sync database:
+
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 -Sy
+
==== aria2 ====
  
Start database generation by installing locally available package files from {{ic|files.list}}:
+
[[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.
  
# recovery-pacman -U $(< files.list)
+
{{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]].}}
  
Install the rest from {{ic|pkglist}}:
+
Install {{Pkg|aria2}}, then edit {{ic|/etc/pacman.conf}} by adding the following line to the {{ic|[options]}} section:
  
  # recovery-pacman -S $(< pkglist)
+
  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
  
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.
+
{{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.}}
  
# pacman -D --asdeps $(pacman -Qq)
+
See [http://aria2.sourceforge.net/manual/en/html/aria2c.html#options OPTIONS] in {{man|1|aria2c}} for used aria2c options.
# pacman -D --asexplicit $(pacman -Qtq)
 
  
Optionally check all installed packages for corruption:
+
* {{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 -Qk
+
==== Other applications ====
  
Optionally [[#Identify files not owned by any package]].
+
There are other downloading applications that you can use with ''pacman''. Here they are, and their associated XferCommand settings:
  
Update all packages:
+
* {{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)
  
# pacman -Su
+
== Utilities ==
  
=== Recovering a USB key from existing install ===
+
* {{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|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}}}}
  
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)
+
=== Graphical front-ends ===
 
 
# pacman -S $(pacman -Qq --dbpath /newarch/var/lib/pacman) --root /newarch --dbpath /newarch/var/lib/pacman
 
 
 
=== Extracting contents of a .pkg file ===
 
 
 
The {{ic|.pkg}} files ending in {{ic|.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 {{ic|.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 {{ic|/etc/conf.d/ntpd.conf}} supplied within the {{Pkg|ntp}} package:
+
{{Warning|1=Some front-ends such as {{AUR|octopi}} [https://github.com/aarnt/octopi/issues/134#issuecomment-142099266] perform [[partial upgrade]]s periodically.}}
  
$ tar -xOf /var/cache/pacman/pkg/ntp-4.2.6.p5-6-i686.pkg.tar.xz etc/conf.d/ntpd.conf
+
* {{App|1=Aarchup|2=Fork of archup. Has the same options as archup plus a few other features. For differences between both please check [https://bbs.archlinux.org/viewtopic.php?id=119129 changelog].|3=https://github.com/aericson/aarchup/|4={{AUR|aarchup}}}}
Or you can use vim, then browse the archive:
+
* {{App|Arch-Update|Update indicator for Gnome-Shell.|https://github.com/RaphaelRochet/arch-update|{{AUR|gnome-shell-extension-arch-update}}}}
$ vim /var/cache/pacman/pkg/ntp-4.2.6.p5-6-i686.pkg.tar.xz
+
* {{App|Arch-Update-Notifier| Update indicator for KDE.|https://github.com/I-Dream-in-Code/kde-arch-update-plasmoid|{{AUR|plasma5-applets-kde-arch-update-notifier-git}}}}
 +
* {{App|Discover|A collection of package management tools for KDE, using PackageKit.|https://projects.kde.org/projects/kde/workspace/discover|{{Pkg|discover}}}}
 +
* {{App|GNOME packagekit|GTK based package management tool|http://www.freedesktop.org/software/PackageKit/|{{Pkg|gnome-packagekit}}}}
 +
* {{App|GNOME Software|Gnome Software App. (Curated selection for GNOME)|https://wiki.gnome.org/Apps/Software|{{pkg|gnome-software}}}}
 +
* {{App|kalu|A small application that will add an icon to your systray and sit there, regularly checking if there's anything new for you to upgrade.|https://jjacky.com/kalu/|{{aur|kalu}}}}
 +
* {{App|pcurses|Package management in a curses frontend|https://github.com/schuay/pcurses|{{Pkg|pcurses}}}}
 +
* {{App|1=PkgBrowser|2=Application for searching and browsing Arch packages, showing details on selected packages.|3=https://bitbucket.org/kachelaqa/pkgbrowser/wiki/Home|4={{AUR|pkgbrowser}}}}
 +
* {{App|tkPacman|Depends only on Tcl/Tk and X11, and interacts with the package database via the CLI of ''pacman''.|http://sourceforge.net/projects/tkpacman|{{AUR|tkpacman}}}}

Latest revision as of 12:33, 14 June 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 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): 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

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 '-(cvs|svn|git|hg|bzr|darcs)$'

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. The general process for doing so is:

  1. Create a sorted list of the files you want to check ownership of:
    $ find /etc /opt /usr | sort > all_files.txt
  2. Create a sorted list of the files tracked by pacman (and remove the trailing slashes from directories):
    $ pacman -Qlq | sed 's|/$||' | sort > owned_files.txt
  3. Find lines in the first list that are not in the second:
    $ comm -23 all_files.txt owned_files.txt

This process is tricky in practice because many important files are not part of any package (e.g. files generated at runtime, custom configs) and so will be included in the final output, making it difficult to pick out the files that can be safely deleted.

Tip: The lostfiles script performs similar steps, but also includes an extensive blacklist to remove common false positives from the output. aconfmgr (aconfmgr-gitAUR) also allows tracking 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, not only backup files.

Back-up the pacman database

The following command can be used to back up 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.

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.

Note: 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.local: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.local: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 Resilio Sync or Syncthing 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 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 Linux Archive for alternatives.

Tip: bacman honours the PACKAGER, PKGDEST and PKGEXT options from makepkg.conf. Bacman does not currently honor the COMPRESS options in makepkg.conf.

An alternative tool would be fakepkgAUR. It supports parallelization and can handle multiple input packages in one command, which bacman both does not support.

List of installed packages

Keeping a list of explicitly installed packages can be useful to speed up installation on a new system:

$ pacman -Qqe > pkglist.txt
Note: If the option -t was used, when reinstalling the list all the non-top-level packages would be set as dependencies. With option -n, foreign packages (e.g. from AUR) would be omitted from the list.

To install packages from the list backup, run:

# pacman -S - < pkglist.txt
Tip:
  • To skip already installed packages, use --needed.
  • 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.

In case the list includes foreign packages, such as AUR packages, remove them first:

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

To remove all the packages on your system that are not mentioned in the list:

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

If you would like 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/packages.txt'

Listing all changed files from packages

If you are suspecting file corruption (e.g. by software/hardware failure), but are unsure if files were got 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 -Qnq | pacman -S -

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

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
  • 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

Graphical front-ends

Warning: Some front-ends such as octopiAUR [2] perform partial upgrades periodically.
  • Aarchup — Fork of archup. Has the same options as archup plus a few other features. For differences between both please check changelog.
https://github.com/aericson/aarchup/ || aarchupAUR
  • Arch-Update — Update indicator for Gnome-Shell.
https://github.com/RaphaelRochet/arch-update || gnome-shell-extension-arch-updateAUR
  • Arch-Update-Notifier — Update indicator for KDE.
https://github.com/I-Dream-in-Code/kde-arch-update-plasmoid || plasma5-applets-kde-arch-update-notifier-gitAUR
  • Discover — A collection of package management tools for KDE, using PackageKit.
https://projects.kde.org/projects/kde/workspace/discover || discover
  • GNOME packagekit — GTK based package management tool
http://www.freedesktop.org/software/PackageKit/ || gnome-packagekit
  • GNOME Software — Gnome Software App. (Curated selection for GNOME)
https://wiki.gnome.org/Apps/Software || gnome-software
  • kalu — A small application that will add an icon to your systray and sit there, regularly checking if there's anything new for you to upgrade.
https://jjacky.com/kalu/ || kaluAUR
  • pcurses — Package management in a curses frontend
https://github.com/schuay/pcurses || pcurses
  • PkgBrowser — Application for searching and browsing Arch packages, showing details on selected packages.
https://bitbucket.org/kachelaqa/pkgbrowser/wiki/Home || pkgbrowserAUR
  • tkPacman — Depends only on Tcl/Tk and X11, and interacts with the package database via the CLI of pacman.
http://sourceforge.net/projects/tkpacman || tkpacmanAUR