Some useful APT commands
The APT package manager used in the Debian and Ubuntu Linux distros keeps track of installed packages, but it also which files they installed. Here are four package management commands I have ended up using regularly.
What package does this file belong to?
If you know the path to a file (for example a configuration file) you
can find name of the package it belongs to by running
$ dpkg -S /etc/smartd.conf smartmontools: /etc/smartd.conf
In this example the
smartmontools package provides the
You might want to know which package provides a tool you have been
using. A common scenario is when you have a tool available on your
computer, you want to run it on another computer, and you don't recall
how you installed the tool. Simply pass the command name through the
which command to get the full path and use
dpkg again to find the
$ dpkg -S `which sendmail` msmtp-mta: /usr/sbin/sendmail
In this example the
msmtp-mta package provides the
command. In general, the package name might not be obvious, especially
if multiple packages can provide the same file.
Which package version do I have?
Checking which version of a package you gave installed is useful for
knowing which features are supported by that version. The version is
easily checked check using
apt-cache when you have the package name:
$ apt-cache policy msmtp-mta msmtp-mta: Installed: 1.8.6-1 Candidate: 1.8.6-1 Version table: *** 1.8.6-1 500 500 http://se.archive.ubuntu.com/... 100 /var/lib/dpkg/status
In this example the version of the installed
msmtp-mta package is
What files did the package install?
Sometimes you know that a package did install something, but not
exacly where. This could be an example file, documentation, a utility
command, an init script, a library, etc. Given a package name the
dpkg command can list the files that the package installed:
$ dpkg -L endlessh /. /etc /etc/init.d /etc/init.d/endlessh /lib /lib/systemd /lib/systemd/system /lib/systemd/system/endlessh.service /usr /usr/bin /usr/bin/endlessh /usr/share /usr/share/doc /usr/share/doc/endlessh /usr/share/doc/endlessh/README.Debian /usr/share/doc/endlessh/changelog.Debian.gz /usr/share/doc/endlessh/copyright /usr/share/man /usr/share/man/man1 /usr/share/man/man1/endlessh.1.gz
From this output we can see that the
endlessh package provides an
init script, a
systemd service unit file, a binary, a readme file, a
changelog, a license file, and a manpage.
How do I keep track of manually installed files?
Sometimes you need to install something that is not available as a
package. Luckily, there's a tool called
checkinstall that acts as a
glue between a command that install files and the APT package
manager. You typically invoke it like this:
$ cd some-package $ ./configure $ make $ sudo checkinstall make install
checkinstall command wraps the
make install command one
would usually run. The file system is scanned for new files created by
the installation command. The created files are then added to a new
APT package. When you run
checkinstall you get to fill in the
details of the package (name, version, maintainer, etc).
The source directory can be deleted at this point. Once the files are installed and owned properly by a package it is now easy to uninstall previously installed files - simply uninstall the package!