Check whether a package is installed

[alienspy]

Hello! As a noob and non-techy i have been using for a long time apt install command for finding out whether a package is installed.

apt install nano, oh, it is already installed, cool, ok.

Now i try to educate myself and read the Debian Administrator's Handbook. So i am looking for a more appropriate alternative.

For example in Handbook is mentioned apt-cache policy packagename command

Lets test three options. Package is installed (nano is installed on my system). Not installed (vim is not installed). Package is probably installed, but i have forgot the full name. Gnome-text-editor is installed. But i won't enter the full name.

apt-cache policy packagename. It shows both installed and non-installed packages. For example i see that nano is installed, and vim is not. But if i enter gnome-text-ed (editor) it gives me "N: Unable to locate package gnome-text-ed"

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$ apt-cache policy nano
nano:
  Installed: 7.2-1
  Candidate: 7.2-1
  Version table:
 *** 7.2-1 500
        500 https://deb.debian.org/debian bookworm/main amd64 Packages
        100 /var/lib/dpkg/status

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$ apt-cache policy vim
vim:
  Installed: (none)
  Candidate: 2:9.0.1378-2
  Version table:
     2:9.0.1378-2 500
        500 https://deb.debian.org/debian bookworm/main amd64 Packages

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$ apt-cache gnome-text-ed
E: Invalid operation gnome-text-ed

apt search packagename understands that i want gnome-text-ed(itor). But for nano and vim its output is huge and irrelevant.

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$ apt search nano
Sorting... Done
Full Text Search... Done
alpine-pico/stable 2.26+dfsg-1 amd64
  Simple text editor from Alpine, a text-based email client

arduino-core-avr/stable,stable 1.8.6+dfsg-1 all
  Arduino Core for AVR microcontroller

bornagain/stable 1.19.0-3+b5 amd64
  Simulate and fit X-ray and neutron GISAS -- binary........

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$ apt search gnome-text-ed
Sorting... Done
Full Text Search... Done
gnome-text-editor/stable,now 43.2-1 amd64 [installed]
  simple text editor for GNOME

apt list -a packagename has the same problem as apt-cache policy. It shows (not)installed files, but fails to understand incomplete package names.

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$ apt list -a nano
Listing... Done
nano/stable,now 7.2-1 amd64 [installed]

nano/stable 7.2-1 i386

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$ apt list -a vim
Listing... Done
vim/stable 2:9.0.1378-2 amd64

vim/stable 2:9.0.1378-2 i386

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$ apt list -a gnome-text-ed
Listing... Done

Some even advise which packagename, but it just shows no output for non-installed packages, which can be confused with a mistake.

apt list | grep packagename works fine in general. But again it gives huge list for nano and vim. Though it understands "text-edito"

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$ apt list | grep nano

libghc-nanospec-dev/stable 0.2.2-4+b1 amd64
libghc-nanospec-dev/stable 0.2.2-4+b1 i386
libghc-nanospec-doc/stable,stable 0.2.2-4 all...

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$ apt list | grep gnome-text-ed

gnome-text-editor/stable,now 43.2-1 amd64 [installed]
gnome-text-editor/stable 43.2-1 i386

Also there is

dpkg -l | grep -i packagename

It understands incomplete package name. But i can't understand its output for vim. "ii means "It should be installed and it is installed"" (src). Does it mean that vim is partially installed? "Common" files and "compact" version? apt install wants me to install only vim-runtime.

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$ dpkg -l | grep nano
ii  nano                                               7.2-1                                amd64        small, friendly text editor inspired by Pico

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$ dpkg -l | grep vim
ii  vim-common                                         2:9.0.1378-2                         all          Vi IMproved - Common files
ii  vim-tiny                                           2:9.0.1378-2                         amd64        Vi IMproved - enhanced vi editor - compact version

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$ dpkg -l | grep gnome-text-ed
ii  gnome-text-editor                                  43.2-1                               amd64        simple text editor for GNOME

Lets try Konsole (not installed) instead of vim

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$ dpkg -l | grep konsole
$

No output. So it says nothing if the package is not installed. Not good.

But last two options are not a single commands unfortunately, but a combination of commands. Possible to remember, though, after a number of uses, i think.

What commands do you use for this purpose? Some articles even advise bash scripts for that.

[amin11]

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apt list -i *package_name*

For example

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apt list -i *vim*

[fabien]

apt-cache policy packagename. It shows both installed and non-installed packages. For example i see that nano is installed, and vim is not. But if i enter gnome-text-ed (editor) it gives me "N: Unable to locate package gnome-text-ed"

apt-cache policy and apt-cache list support glob, see man 7 glob

list
list is somewhat similar to dpkg-query --list in that it can display a list of packages satisfying certain criteria. It supports glob(7) patterns for matching package names as well as options to list installed (--installed), upgradeable (--upgradeable) or all available (--all-versions) versions.

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$> apt list "*text-edit*"
Listing... Done
gnome-text-editor/stable 43.2-1 amd64
$> apt policy "gnome-text-edit*"
gnome-text-editor:
  Installed: (none)
  Candidate: 43.2-1
  Version table:
     43.2-1 500
        500 https://deb.debian.org/debian bookworm/main amd64 Packages

apt search understands regular expressions (regex), see man 1 grep

search (apt-cache(8))
search can be used to search for the given regex(7) term(s) in the list of available packages and display matches.

search performs a full text search on all available package lists for the POSIX regex pattern given, see regex(7). It searches the package names and the descriptions for an occurrence of the regular expression

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$> apt search ".*text-edit.*"
Sorting... Done
Full Text Search... Done
gnome-text-editor/stable 43.2-1 amd64
  simple text editor for GNOME

jove/stable 4.17.5.1-2 amd64
  Jonathan's Own Version of Emacs - a compact, powerful editor

wadc/stable 3.1-1 all
  programming environment for creating Doom maps

You can search on package names only

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$> apt --names-only search ".*text-edit.*"
Sorting... Done
Full Text Search... Done
gnome-text-editor/stable 43.2-1 amd64
  simple text editor for GNOME

apt search packagename understands that i want gnome-text-ed(itor). But for nano and vim its output is huge and irrelevant.

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$> apt search "^nano$|^vim$"
Sorting... Done
Full Text Search... Done
nano/stable,now 7.2-1 amd64 [installed]
  small, friendly text editor inspired by Pico

vim/stable,now 2:9.0.1378-2 amd64 [installed]
  Vi IMproved - enhanced vi editor

Some even advise which packagename, but it just shows no output for non-installed packages, which can be confused with a mistake.

which is different and has nothing to do with package search.

DESCRIPTION
which returns the pathnames of the files (or links) which would be executed in the current environment

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$> which csplit
/usr/bin/csplit
$> apt search "csplit"
Sorting... Done
Full Text Search... Done
coreutils/stable,now 9.1-1 amd64 [installed]
  GNU core utilities

apt list | grep packagename works fine in general. But again it gives huge list for nano and vim. Though it understands "text-edito"

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$> apt list | grep "^nano/\|^vim/\|^[^/]\+text-edito[^/]\+/"

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

gnome-text-editor/stable 43.2-1 amd64
nano/stable,now 7.2-1 amd64 [installed]
vim/stable,now 2:9.0.1378-2 amd64 [installed]

Also there is

dpkg -l | grep -i packagename

It understands incomplete package name. But i can't understand its output for vim. "ii means "It should be installed and it is installed"" (src). Does it mean that vim is partially installed?

dpkg -l lists only installed packages, or packages that have been removed but not purged (rc), or packages in an error state, or marked for installation... The explanation of the codes is in the header.

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$> dpkg -l | head -n5
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                                 Version                              Architecture Description
+++-====================================-====================================-============-===========

In your case, vim is not installed, in my case it is.

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$> dpkg -l | grep "vim"
ii  vim                                  2:9.0.1378-2                         amd64        Vi IMproved - enhanced vi editor
ii  vim-common                           2:9.0.1378-2                         all          Vi IMproved - Common files
ii  vim-runtime                          2:9.0.1378-2                         all          Vi IMproved - Runtime files
ii  vim-tiny                             2:9.0.1378-2                         amd64        Vi IMproved - enhanced vi editor - compact version

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$> dpkg -l | grep "^ii.[[:blank:]]vim[[:blank:]]"
ii  vim                                  2:9.0.1378-2                         amd64        Vi IMproved - enhanced vi editor

What commands do you use for this purpose? Some articles even advise bash scripts for that.

All these commands, and I also have my own super secret scripts

[alienspy]

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apt list -i *package_name*

For example

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apt list -i *vim*

Yes, but it has the downside that you cant search for an incomplete name or a slightly wrong name of a package.

[alienspy]

All these commands, and I also have my own super secret scripts

Wow, much to learn! Thanks

[sunrat]

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apt list -i *package_name*

For example

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apt list -i *vim*

Yes, but it has the downside that you cant search for an incomplete name or a slightly wrong name of a package.

Asterisks are wildcards. It will search incomplete names but not slightly wrong names. Try

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$ apt list -i *image*

[pbear]

My preferred command is a variant of one already mentioned: apt list --installed | grep xyz, where xyz can be any part of the package name, no wildcards or globs required.
Synaptic package manager has a search function and sometimes I use that (mainly if I expect to use Synaptic after doing the search).

[mrmazda]

My preferred command is a variant of one already mentioned: apt list --installed | grep xyz, where xyz can be any part of the package name, no wildcards or globs required.

Kinda like mine:

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# alias | grep pkg
alias Dq='echo dpkg-query -l ; dpkg-query -l | grep '

[Bulkley]

I use a package browser called packagesearch. It's quick, easy and informative.

[Dai_trying]

I don't know if this will add anything to the thread but I often use dpkg with the parameter --get selections piped into grep to check on installed packages.

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$ dpkg --get-selections | grep apt
apt						install
apt-file					install
apt-listchanges					install
apt-transport-https				install
apt-utils					install
laptop-detect					install
libapt-pkg-perl					install
libapt-pkg6.0:amd64				install
libatk-adaptor:amd64				install
libfreeaptx0:amd64				install
libraptor2-0:amd64				install
python-apt-common				install
python3-apt					install
synaptic					install
task-laptop					install

[lindi]

You can use dpkg-query without grep quite efficiently:

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$ time dpkg-query -Wf '${db:Status-Status}' apt
installed
real	0m0.030s
user	0m0.023s
sys	0m0.007s

[Dai_trying]

You can use dpkg-query without grep quite efficiently:

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$ time dpkg-query -Wf '${db:Status-Status}' apt
installed
real	0m0.030s
user	0m0.023s
sys	0m0.007s

The only issue with this (for me) would be that you must enter the exact package name and it doesn't list other similar named packages (which is my preference) but it probably answers the OP more exactly.