Difference between revisions of "Pacman/Tips and tricks"

Revision as of 21:47, 31 August 2013

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Cosmetic and Convienence

Color output

As of version 4.1, Pacman has a color option. Uncomment the "Color" line in pacman.conf.

Shortcuts

The following instructions allow users to run some of the more common pacman commands without the need to type them fully via a script alias.

Configure the shell

Add the following examples, which work in both Bash and Zsh:

 # Pacman alias examples
 alias pacupg='sudo pacman -Syu'        # Synchronize with repositories and then upgrade packages that are out of date on the local system.
 alias 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
 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

Usage

Perform the respective commands by simply typing the alias name. For example, to synchronize with repositories and then upgrade packages that are out of date on the local system:

$ pacupg

Install packages from repositories:

$ pacin <package1> <package2> <package3>

Install a custom built package:

$ pacins /path/to/<package>

Completely remove a locally installed package:

$ pacrem <package>

Search for available packages in the repositories:

$ pacreps <keywords>

Display information about a package (e.g. size, dependencies) in the repositories:

$ pacrep <keywords>

Notes

The aliases used above are merely examples. By following the syntax samples above, rename the aliases as convenient. For example:

alias pacrem='sudo pacman -Rns'
alias pacout='sudo pacman -Rns'

In the case above, the commands pacrem and pacout both call your shell to execute the same command.

Operations and Bash syntax

In addition to pacman's standard set of features, there are ways to extend its usability through rudimentary Bash commands/syntax.

• To install a number of packages sharing similar patterns in their names -- not the entire group nor all matching packages; eg. kde:

# pacman -S kde-{applets,theme,tools}

• Of course, that is not limited and can be expanded to however many levels needed:

# pacman -S kde-{ui-{kde,kdemod},kdeartwork}

• Sometimes, -s's builtin ERE can cause a lot of unwanted results, so it has to be limited to match the package name only; not the description nor any other field:

# pacman -Ss '^vim-'

• pacman has the -q operand to hide the version column, so it is possible to query and reinstall packages with "compiz" as part of their name:

# pacman -S $(pacman -Qq | grep compiz)

• Or install all packages available in a repository (kde-unstable for example):

# pacman -S $(pacman -Slq kde-unstable)

Maintenance

House keeping, in the interest of keeping a clean system and following The Arch Way

Listing all installed packages with size

• You may want to get the list of installed packages sorted by size, which may be useful when freeing space on your hard drive.
• Use pacsysclean from pacman package.
• Install expac and run 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].
• pacman -Qi | egrep "^(Name|Installed Size)" | sed -e 'N;s/\n/ /' | awk '{ print $7, $3}' | sort -n

Listing installed packages with version

• You may want to get the list of installed packages with their version, which is useful when reporting bugs or discussing installed packages.
• List all explicitly installed packages: pacman -Qe .
• List all foreign packages (typically manually downloaded and installed): pacman -Qm .
• List all native packages (installed from the sync database(s)): pacman -Qn .
• List packages by regex: pacman -Qs <regex> | awk 'BEGIN { RS="\n" ; FS="/" } { print $2 }' | awk '{ if(NF > 0) print $1, $2 }'
• Install expac and run expac -s "%-30n %v"

Identify files not owned by any package

Periodic checks for files outside of pacman database are recommended. These files are often some 3rd party applications installed using the usual procedure (e.g. ./configure && make && make install). Search the file-system for these files (or symlinks) using this simple script:

pacman-disowned

#!/bin/sh

tmp=${TMPDIR-/tmp}/pacman-disowned-$UID-$$
db=$tmp/db
fs=$tmp/fs

mkdir "$tmp"
trap 'rm -rf "$tmp"' EXIT

pacman -Qlq | sort -u > "$db"

find /bin /etc /sbin /usr \
  ! -name lost+found \
  \( -type d -printf '%p/\n' -o -print \) | sort > "$fs"

comm -23 "$fs" "$db"

To generate the list:

$ pacman-disowned > non-db.txt

Note that one should not delete all files listed in non-db.txt without confirming each entry. There could be various configuration files, logs, etc., so use this list responsibly and only proceed after extensively searching for cross-references using grep.

Removing orphaned packages

For recursively removing orphans:

# pacman -Rs $(pacman -Qtdq)

The following alias is easily inserted into ~/.bashrc and removes orphans if found:

~/.bashrc

# '[r]emove [o]rphans' - recursively remove ALL orphaned packages
alias pacro="/usr/bin/pacman -Qtdq > /dev/null && sudo /usr/bin/pacman -Rs \$(/usr/bin/pacman -Qtdq | sed -e ':a;N;\$!ba;s/\n/ /g')"

The following function is easily inserted into ~/.bashrc and removes orphans if found:

~/.bashrc

orphans() {
  if [[ ! -n $(pacman -Qdt) ]]; then
    echo "No orphans to remove."
  else
    sudo pacman -Rs $(pacman -Qdtq)
  fi
}

Removing everything but base group

If it is ever necessary to remove all packages except the base group, try this one liner:

# pacman -Rs $(comm -23 <(pacman -Qeq|sort) <((for i in $(pacman -Qqg base); do pactree -ul $i; done)|sort -u|cut -d ' ' -f 1))

Source: Look at discussion here

Notes:

1. comm requires sorted input otherwise you get e.g. comm: file 1 is not in sorted order.
2. pactree prints the package name followed by what it provides. For example:

$ pactree -lu logrotate

logrotate
popt
glibc
linux-api-headers
tzdata
dcron cron
bash
readline
ncurses
gzip

The dcron cron line seems to cause problems, that is why cut -d ' ' -f 1 is needed - to keep just the package name.

Listing official installed packages only

pacman -Qqn

This list packages that are found in the sync database(s). If the user has unofficial repositories configured, it will list packages from such repositories too.

Getting the dependencies list of several packages

Dependencies are alphabetically sorted and doubles are removed. Note that you can use pacman -Qi to improve response time a little. But you won't be able to query as many packages. Unfound packages are simply skipped (hence the 2>/dev/null). You can get dependencies of AUR packages as well if you use yaourt -Si, but it will slow down the queries.

$ pacman -Si $@ 2>/dev/null | awk -F ": " -v filter="^Depends" \ '$0 ~ filter {gsub(/[>=<][^ ]*/,"",$2) ; gsub(/ +/,"\n",$2) ; print $2}' | sort -u

Alternatively, you can use expac: expac -l '\n' %E -S $@ | sort -u.

Getting the size of several packages

You can use (and tweak) this little shell function:

~/.bashrc

pacman-size()
{
	CMD="pacman -Si"
	SEP=": "
	TOTAL_SIZE=0
	
	RESULT=$(eval "${CMD} $@ 2>/dev/null" | awk -F "$SEP" -v filter="^Size" -v pkg="^Name" \
	  '$0 ~ pkg {pkgname=$2} $0 ~ filter {gsub(/\..*/,"") ; printf("%6s KiB %s\n", $2, pkgname)}' | sort -u -k3)
	
	echo "$RESULT"
	
	## Print total size.
	echo "$RESULT" | awk '{TOTAL=$1+TOTAL} END {printf("Total : %d KiB\n",TOTAL)}'
}

As told for the dependencies list, you can use pacman -Qi instead, but not yaourt since AUR's PKGBUILD do not have size information.

A nice one-liner:

$ pacman -Si "$@" 2>/dev/null | awk -F ": " -v filter="Size" -v pkg="Name" '$0 ~ pkg {pkgname=$2} $0 ~ filter {gsub(/\..*/,"") ; printf("%6s KiB %s\n", $2, pkgname)}' | sort -u -k3 | tee >(awk '{TOTAL=$1+TOTAL} END {printf("Total : %d KiB\n",TOTAL)}')

You should replace "$@" with packages, or put this line in a shell function.

Listing changed configuration files

If you want to backup your system configuration files you could copy all files in /etc/, but usually you'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.

changed-files.sh

#!/bin/bash
for package in /var/lib/pacman/local/*; do
	sed '/^%BACKUP%$/,/^%/!d' $package/files | tail -n+2 | grep -v '^$' | while read file hash; do
		[ "$(md5sum /$file | (read hash file; echo $hash))" != "$hash" ] && echo $(basename $package) /$file
	done
done

Listing a package's files that have been modified, removed, touched, or chmodded

Pacman has the new QUERY option -k (read more in `man pacman` under the QUERY section). For example, run

# pacman -Qk some-package

to see which files belonging to some-package have are present on the system. Run

# pacman -Qkk some-package

to see more detailed information like which files belonging to some-package have had their sizes modified, their modification times changed, or their permissions changed).

Listing all packages that nothing else depends on

If you want to generate a list of all installed packages that nothing else depends on, you can use the following script. This is very helpful if you are trying to free hard drive space and have installed a lot of packages that you may not remember. You can browse through the output to find packages which you no longer need.

clean

#!/bin/bash

# This script is designed to help you clean your computer from unneeded
# packages. The script will find all packages that no other installed package
# depends on. It will output this list of packages excluding any you have
# placed in the ignore list. You may browse through the script's output and
# remove any packages you do not need.

# Enter groups and packages here which you know you wish to keep. They will
# not be included in the list of unrequired packages later.
ignoregrp="base base-devel"
ignorepkg=""

# 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

If you install expac you can run expac "%n %N" -Q $(expac "%n %G" | grep -v ' base') | awk '$2 == "" {print $1}' which should give the same results but much faster.

The following script has the option to exclude files like above, but uses expac:

clean

#!/bin/bash

# Generate list of installed packages (leaves in package dependency tree).
# Give it a list with packages that should be ignored in the final list, each
# package on a separate line.

# Temporary files
IGNORED=$(mktemp)
[ -n "$1" ] && cat "$1" >$IGNORED
LIST="$(mktemp)"

expac "%n %N" -Q $(expac "%n %G" | grep -v ' base') | awk '$2 == "" {print $1}' > "$LIST"

# Sort both lists, so they can be diffed.
TMPF=$(mktemp)
sort "$IGNORED" | grep -v '^$' > "$TMPF"
sort -o "$LIST" "$LIST"
IGNORED="$TMPF"
# Diff the lists.
comm -13 "$IGNORED" "$LIST"

Backing up Local database with systemd

systemd can take snapshots of the pacman local database everytime it is modified.

#!/bin/bash

declare -r pakbak="/pakbak.tar.xz";  ## set backup location
tar -cJf "$pakbak" "/var/lib/pacman/local";  ## compress & store pacman local database in $pakbak

[Unit]
Description=Back up pacman database

[Service]
Type=oneshot
ExecStart=/bin/bash /usr/lib/systemd/scripts/pakbak_script
RemainAfterExit=no

[Unit]
Description=Back up pacman database

[Path]
PathChanged=/var/lib/pacman/local
Unit=pakbak.service

[Install]
WantedBy=multi-user.target

# systemctl start pakbak.path

# systemctl enable pakbak.path

Installation and recovery

Alternative ways of getting and restoring packages.

Installing packages from a CD/DVD or USB stick

To download packages, or groups of packages:

# cd ~/Packages
# pacman -Syw base base-devel grub-bios xorg gimp --cachedir .
# repo-add ./custom.db.tar.gz ./*

Then you can burn the "Packages" folder to a CD/DVD or transfer it to a USB stick, external HDD, etc.

To install:

1. Mount the media:

# mkdir /mnt/repo
# mount /dev/sr0 /mnt/repo    #For a CD/DVD.
# mount /dev/sdxY /mnt/repo   #For a USB stick.

2. Edit pacman.conf and add this repository before the other ones (e.g. extra, core, etc.). This is important. 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:

# nano /etc/pacman.conf

[custom]
SigLevel = PackageRequired
Server = file:///mnt/repo/Packages

3. Finally, synchronize the pacman database to be able to use the new repository:

# pacman -Sy

Custom local repository

pacman 3 introduced a new script named repo-add which makes generating a database for a personal repository much easier. Use repo-add --help for more details on its usage.

Simply store all of the built packages to be included in the repository in one directory, and execute the following command (where repo is the name of the custom repository):

$ repo-add /path/to/repo.db.tar.gz /path/to/*.pkg.tar.xz

Note that when using 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.

To add a new package (and remove the old if it exists), run:

$ repo-add /path/to/repo.db.tar.gz /path/to/packagetoadd-1.0-1-i686.pkg.tar.xz

Once the local repository has been made, add the repository to pacman.conf. The name of the db.tar.gz file is the repository name. Reference it directly using a file:// url, or access it 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

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: darkhttpd /var/cache/pacman/pkg. Just add this server at the top of your mirror list. Be aware that you might get a lot of 404 errors, due to cache misses, depending on what you do, but pacman will try the next (real) mirrors when that happens.

Read-write cache

In order to share packages between multiple computers, simply share /var/cache/pacman/ using any network-based mount protocol. This section shows how to use shfs or sshfs to share a package cache plus the related library-directories between multiple computers on the same local network. Keep in mind that a network shared cache can be slow depending on the file-system choice, among other factors.

First, install any network-supporting filesystem; for example sshfs, shfs, ftpfs, smbfs or nfs.

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

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

Backing up and retrieving a list of installed packages

It is good practice to keep periodic backups of all pacman-installed packages. In the event of a system crash which is unrecoverable by other means, pacman can then easily reinstall the very same packages onto a new installation.

• First, backup the current list of non-local packages:

$ pacman -Qqen > pkglist.txt

• Store the pkglist.txt on a USB key or other convenient medium or gist.github.com or Evernote, Dropbox, etc.

• Copy the pkglist.txt file to the new installation, and navigate to the directory containing it.

• Issue the following command to install from the backup list:

# pacman -S $(< pkglist.txt)

In the case you have a list which was not generated like mentioned above, there may be foreign packages in it (i.e. packages not belonging to any repos you have configured, or packages from the AUR).

In such a case, you may still want to install all available packages from that list:

# pacman -S --needed $(comm -12 <(pacman -Slq|sort) <(sort badpkdlist) )

Explanation:

• pacman -Slq lists all available softwares, but the list is sorted by repository first, hence the sort command.
• Sorted files are required in order to make the comm command work.
• The -12 parameter display lines common to both entries.
• The --needed switch is used to skip already installed packages.

You may also try to install all unavailable packages (those not in the repos) from the AUR using yaourt (not recommended unless you know exactly what you are doing):

$ yaourt -S --needed $(comm -13 <(pacman -Slq|sort) <(sort badpkdlist) )

Finally, you may want to remove all the packages on your system that are not mentioned in the list.

# pacman -Rsu $(comm -23 <(pacman -Qq|sort) <(sort pkglist))

List downloaded packages that are not in base or base-devel

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:

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

Reinstalling all packages

To reinstall all native packages, use:

# pacman -Qenq | pacman -S -

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

Pacman preserves the installation reason by default.

Restore pacman's local database

Signs that pacman needs a local database restoration:

• pacman -Q gives absolutely no output, and pacman -Syu erroneously reports that the system is up to date.
• When trying to install a package using pacman -S package, and it outputs a list of already satisfied dependencies.
• When testdb (part of pacman) reports database inconsistency.

Most likely, pacman's database of installed software, /var/lib/pacman/local, has been corrupted or deleted. While this is a serious problem, it can be restored by following the instructions below.

Firstly, make sure pacman's log file is present:

$ ls /var/log/pacman.log

If it does not exist, it is not possible to continue with this method. You may be able to use Xyne's package detection script to recreate the database. If not, then the likely solution is to re-install the entire system.

Log filter script

pacrecover

#!/bin/bash -e

. /etc/makepkg.conf

PKGCACHE=$((grep -m 1 '^CacheDir' /etc/pacman.conf || echo 'CacheDir = /var/cache/pacman/pkg') | sed 's/CacheDir = //')

pkgdirs=("$@" "$PKGDEST" "$PKGCACHE")

while read -r -a parampart; do
  pkgname="${parampart[0]}-${parampart[1]}-*.pkg.tar.xz"
  for pkgdir in ${pkgdirs[@]}; do
    pkgpath="$pkgdir"/$pkgname
    [ -f $pkgpath ] && { echo $pkgpath; break; };
  done || echo ${parampart[0]} 1>&2
done

Make the script executable:

$ chmod +x pacrecover

Generating the package recovery list

Run the script (optionally passing additional directories with packages as parameters):

$ paclog-pkglist /var/log/pacman.log | ./pacrecover >files.list 2>pkglist.orig

This way two files will be created: files.list with package files, still present on machine and pkglist.orig, packages from which should be downloaded. Later operation may result in mismatch between files of older versions of package, still present on machine, and files, found in new version. Such mismatches will have to be fixed manually.

Here is a way to automatically restrict second list to packages available in a repository:

$ { cat pkglist.orig; pacman -Slq; } | sort | uniq -d > pkglist

Check if some important base package are missing, and add them to the list:

$ comm -23 <(pacman -Sgq base) pkglist.orig >> pkglist

Proceed once the contents of both lists are satisfactory, since they will be used to restore pacman's installed package database; /var/lib/pacman/local/.

Performing the recovery

Define bash alias for recovery purposes:

# recovery-pacman() {
    pacman "$@"       \
    --log /dev/null   \
    --noscriptlet     \
    --dbonly          \
    --force           \
    --nodeps          \
    --needed          \
    #
}

--log /dev/null allows to avoid needless pollution of pacman log, --needed will save some time by skipping packages, already present in database, --nodeps will allow installation of cached packages, even if packages being installed depend on newer versions. Rest of options will allow pacman to operate without reading/writing filesystem.

Populate the sync database:

# pacman -Sy

Start database generation by installing locally available package files from files.list:

# recovery-pacman -U $(< files.list)

Install the rest from pkglist:

# recovery-pacman -S $(< pkglist)

Update the local database so that packages that are not required by any other package are marked as explicitly installed and the other as dependences. You will need be extra careful in the future when removing packages, but with the original database lost is the best we can do.

# pacman -D --asdeps $(pacman -Qq)
# pacman -D --asexplicit $(pacman -Qtq)

Optionally check all installed packages for corruption:

# pacman -Qk

Optionally #Identify files not owned by any package.

Update all packages:

# pacman -Su

Recovering a USB key from existing install

If you have Arch installed on a USB key and manage to mess it up (e.g. removing it while it is still being written to), then it is possible to re-install all the packages and hopefully get it back up and working again (assuming USB key is mounted in /newarch)

# pacman -S $(pacman -Qq --dbpath /newarch/var/lib/pacman) --root /newarch --dbpath /newarch/var/lib/pacman

Extracting contents of a .pkg file

The .pkg files ending in .xz are simply tar'ed archives that can be decompressed with:

$ tar xvf package.tar.xz

If you want to extract a couple of files out of a .pkg file, this would be a way to do it.

Viewing a single file inside a .pkg file

For example, if you want to see the contents of /etc/systemd/logind.conf supplied within the systemd package:

$ tar -xOf /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz etc/systemd/logind.conf

Or you can use vim, then browse the archive:

$ vim /var/cache/pacman/pkg/systemd-204-3-x86_64.pkg.tar.xz