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In order to research what caused the installation of a given package, I'd like to get a list of packages which depend on that package. I couldn't find anything obvious in man dpkg.

Garrett
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l0b0
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  • Related: http://askubuntu.com/questions/13296/how-do-i-find-the-reverse-dependency-of-a-package – Seth Feb 26 '15 at 03:58
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    The older question's answers all revolve around aptitude, something that hasn't been installed by default for years. In 2017, everyone on Ubuntu still has apt-cache. Anyone who follows the linked question is going to get lost in a discussion about a program few will have. – Lambart Aug 18 '17 at 17:48

8 Answers8

482

apt-cache rdepends packagename should do what you want.

To limit it to packages that are installed on your system: apt-cache rdepends --installed packagename

Bram
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RobotHumans
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    Excellent! apt-cache rdepends tofrodos confirmed the suspicion that it was installed by another package (the obsoleted dos2unix). – l0b0 Apr 30 '12 at 13:12
  • Good deal. I do wish there was a recursive option. Sadly there is not as far as I am aware. – RobotHumans Apr 30 '12 at 13:27
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    As for today (apt version 0.9.9.1), there is --recurse option that works with rdepends. – jarno Dec 22 '13 at 14:00
  • Thanks for the heads up. /me is even more pleased than he was. – RobotHumans Dec 22 '13 at 22:50
  • @l0b0: btw, if you only needed to know if a package was installed automatically as a dependency - there is apt-mark showauto available – zerkms Feb 03 '14 at 21:24
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    If you add --installed, the output is even useful for packages which can be used by many others: apt-cache rdepends --installed packagename – quazgar May 27 '14 at 22:08
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    There's a slightly different syntax which helped me to differentiate between Recommends, Depends, Suggests, etc. Syntax is sudo apt rdepends packagename (Notice it is not using apt-cache but simply apt) – Vahid Pazirandeh Nov 16 '17 at 05:26
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    For the output, why do some of the packages have a vertical bar (pipe symbol) before them? – Vahid Pazirandeh Nov 16 '17 at 05:35
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    The command apt-cache rdepends packagename seem not to work in WSL. – Arcticooling Jan 17 '18 at 16:45
  • That sounds like a them problem not a me problem. It works on native systems. – RobotHumans Jan 18 '18 at 10:41
  • Unfortunately, the list is not sorted alphabetically (unlike the result of apt-rdepends --reverse <package name>) and includes reverse dependencies that aren’t installed by default (which I consider strange for a command with “cache” in the name). To address those issues, one can use apt-cache rdepends --installed <package name> | tail --lines=+3 | sort. (The tail command is used to strip the two heading lines, which must be done before the sort occurs.) – Patrick Dark Jun 08 '19 at 22:15
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    To add to the comment by @VahidPazirandeh: apt does not need sudo for operations like rdepends. Just apt rdepends packagename suffices. – Frank Kusters Mar 17 '22 at 09:13
  • @quazgar Unfortunately, --installed does not work as one may think and is rather useless. See my answer. – vinc17 Jan 25 '23 at 11:35
  • Thanks. It seems to repeat dependencies though, so I used it as: apt-cache rdepends texlive-latex-extra | tail -n +3 | sort | uniq. – user643722 Oct 25 '23 at 19:11
96

aptitude has a fairly nice way of handling this:

$ aptitude why bash
i   foomatic-filters PreDepends bash (>= 2.05)

By default, it only lists the "most installed, strongest, tightest, shortest" reason, but you can use aptitude -v why to make it output everything it finds.

n.st
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tumbleweed
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42

The simplest option is still:

apt rdepends package-name

which does not require you to install any package.

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    What is this adding to the accepted answer? – l0b0 Nov 26 '18 at 23:58
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    The accepted answer has nothing to do with this one. The output is completely different and way more useful for human consumption than apt-cache's. The answer mentions that apt-cache is not installed by default everywhere - that alone should be a rather good hint why this answer has its purpose. finally, this is actually the answer I was looking for, so any downvote is rather silly. – stefanct Nov 28 '18 at 13:21
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    One very significant reason why this is better than the accepted version is that it includes the version of the dependencies, unlike apt-caches output. It's exactly what I needed right now (debugging a glibc 2.28 incompatibility, so upvoting) – Per Lundberg Jan 02 '19 at 09:10
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    upvote for using just apt. at the time of the original answer, I'm not sure this just apt solution would have been valid, but if it is now, that's good. – RobotHumans Apr 20 '19 at 11:53
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apt-cache showpkg <pkgname> 

Example:

apt-cache showpkg lightdm
Seth
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qorrow
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There is more than one way, with each method showing a different output.

For a detailed view of the full reverse dependency tree;

aptitude install apt-rdepends
apt-rdepends -r bash

Alternatively;

apt-cache showpkg bash

Or a concise list:

apt-cache rdepends bash
Zanna
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papashou
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  • What exactly does rdepends show in that tree? apt-rdepends php7.0-fpm shows sed. sed doesn't depend on PHP, let alone PHP FPM. – Dan Dascalescu Jan 09 '18 at 23:21
  • It is reverse depends, it means that PHP depends on sed. – Erik Berkun-Drevnig Apr 25 '18 at 03:30
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    Hi guys, actually "apt-rdepends" stands for "recursive dependency". If you want reverse recursive dependency, you have to type : apt-rdepends -r yourPackageNameHere – SebMa Apr 27 '18 at 12:56
  • The apt-cache man page says "rdepends shows a listing of each reverse dependency a package has". Whereas apt-rdepends requires the -r option to do reverse dependencies, as @SebMa says. – NeilG Feb 05 '19 at 03:16
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In addition to other good answers, an apt/apt-get -s does a "simulated" removal (or install).

sudo apt -s remove <pkgname>

Using -s or --simulate to remove (or install) packages, will normally list any dependencies affected. It will show orphaned packages when removing, or needed dependencies when installing, without actually executing the install or remove. Informational only.

B. Shea
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  • apt remove -s php7.0-fpm shows The following additional packages will be installed: apache2 apache2-bin apache2-data libapache2-mod-php7.0 libaprutil1-dbd-sqlite3 libaprutil1-ldap liblua5.1-0. Why would apache get installed if I remove PHP FPM? – Dan Dascalescu Jan 09 '18 at 23:22
  • @DanDascalescu Hmm. Might be a bad install/remove script for apt pkg or might be you have some other dependencies that install apache2 as dep (meaning a webserver is needed - and I believe apache2 is default web server). Could be a few things. Just not sure. Has the smell of a good post on AskUbuntu if you haven't found an answer. – B. Shea Jul 10 '18 at 16:26
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With the reverse-depends command from the package: ubuntu-dev-tools

reverse-depends libjs-openlayers
# For build depends search
reverse-depends -b libjs-openlayers
Reverse-Recommends
* gis-osm

Reverse-Depends

  • cyclograph
  • phpmyadmin
  • sumo-tools

Packages without architectures listed are reverse-dependencies in: amd64, arm64, armhf, i386, ppc64el, s390x

2

Since the --installed option of apt-cache was mentioned in comments of RobotHumans's answer and does not make much sense as the matching is done against all versions, including uninstalled ones (see Debian bug 1029586), here's the solution proposed by Julian Andres Klode to get the reverse dependencies among the installed packages:

apt list '?any-version(?installed?depends(?exact-name(packagename)))'

Note that packagename is just the package name, without architecture information. For instance, libpcre3 works, but not libpcre3:amd64.

vinc17
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