Understating apt get install command in Ubuntu Linux with examples. This posts explains apt-get install command in Linux and apt-get update command in Linux including apt-get install options and update options.
apt-get install options
Before we begin, we must understand the apt-get package.
apt-get – APT package handling utility
apt-get is the command-line tool for handling packages, and may be
considered the user’s “back-end” to other tools using the APT library.
Several “front-end” interfaces exist, such as synaptic and aptitude.
apt-get [options] [-o config=string] [-c=cfgfile] command [pkg]
APT (for Advanced Package Tool) is a set of tools for managing Debian
packages, and therefore the applications installed on your Debian
system. APT makes it possible to install applications, remove
applications and update or upgrade applications up to the latest
APT resolves dependency problems and retrieves requested packages from designated package repositories. APT delegates the actual installation and removal of packages to dpkg.
Used to re-synchronize the package index files from their sources.
The indexes of available packages are fetched from the location(s)
specified in /etc/apt/sources.list. An update should always be performed
before an upgrade or dist-upgrade.
Used to install the newest versions of all packages currently
installed on the system from the sources enumerated in
/etc/apt/sources.list. Packages currently installed with new versions
available are retrieved and upgraded; under no circumstances are
currently installed packages removed, nor are packages that are not
already installed retrieved and installed.
In addition to performing the function of upgrade, this option also
intelligently handles changing dependencies with new versions of
packages; apt-get has a “smart” conflict resolution system, and it will
attempt to upgrade the most important packages at the expense of less
important ones, if necessary.
Clears out the local repository of retrieved package files. It
removes everything but the lock file from /var/cache/apt/archives/ and
/var/cache/apt/archives/partial/. Like clean, autoclean clears out the
local repository of retrieved package files. The difference is that it
only removes package files that can no longer be downloaded, and are
This command removes .deb files for packages that are no longer
installed on your system. Depending on your installation habits,
removing these files from /var/cache/apt/archives may regain a
significant amount of diskspace.
This option is followed by one or more packages desired for
installation. Each package is a package name. All packages required by
the package(s) specified for installation will also be retrieved and
installed. The /etc/apt/sources.list file is used to locate the
repositories for the desired packages. A specific version of a package
can be selected for installation by following the package name with an
equals (=) and the version of the package to select. This will cause
that version to be located and selected for install.
apt-get -f install
This command does the same thing as Edit->Fix Broken Packages in
Synaptic. Do this if you get complaints about packages with “unmet
Remove is identical to install except that packages are removed
instead of installed. Note that removing a package leaves its
configuration files on the system. If a plus sign is appended to the
package name (with no intervening space), the identified package will be
installed instead of removed.
The purge is identical to remove except that packages are removed and
purged (any configuration files are deleted too). Please note that the
command apt-get remove just removes a package and not the configuration
files. Whereas the command apt-get purge removes the package and its
This command is a diagnostic tool. It does an update of the package lists and checks for broken dependencies.