What is apt-get?
apt get list
APT, short for Advanced package Tool, is a package management system.apt get allows you to quickly and easily install, update, and remove software from the command line. Aside from its simplicity, one of the best things about APT is the face that it automatically resolves dependency issues for you.
This means that if the package you are installing requires additional software, apt get will automatically locate and install the additional software.
This is a massive improvement over the old days of “ dependency hell” .
installing software with apt get is very straightforward.
For example, let us assume you want to install the classic network-mapping tool Cheops, Once you know the name of the package you want to install, from the command line you can run apt-get install followed by the name of the software you want to install.
It is always a good idea to run apt-get update before installing software.
This will insure that you are getting the latest version available.
install a Package: Installation of packages using the apt-get tool is quite simple. For example, to install the network scanner nmap, type the following:
To update the local package index type the following:
More with the apt-get
1) apt-get updateupdate is used to resynchronize the package index files from their sources
if you are using a non root user you should add sudo to the beginning of the command and it will look like this sudo apt get update
2) apt-get upgrade
upgrade is used to install the newest versions of all packages currently installed on the system from the sources enumerated in /etc/apt/sources.list.
on a non root user you will always need to add sudo at the beginning of the command
sudo apt get upgrade
3) apt-get dselect-upgrade
dselect-upgrade is used in conjunction with the traditional Debian packaging front-end.
4) apt-get dist-upgrade
dist-upgrade in addition to performing the function of upgrade, 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.
So apt-get dist-upgrade command may remove some packages. The /etc/apt/sources.list file contains a list of locations from which to retrieve desired package files. See also apt_preferences(5) for a mechanism for overriding the general settings for individual packages.
apt get uninstall ? there is no command like that , but the right command is apt-get remove or sudo apt-get remove if you are on a non root user.
5) apt get --purge remove
To uninstall a program, use the “ apt-get remove ” command, which is the general command for uninstalling programs on Linux.
For example, the following command uninstalls nmap and deletes all the configuration files, using the “--purge” command.
and If you don’t want to remove the configuration files, simply leave out the “--purge” command,
example
6) apt get reinstall
You can reinstall a package with apt-get install --reinstall packagename.
This completely removes the package (but not the packages that depend on it) then reinstall's it.
for example if we want to reinstall nmap the command would be like that :
7) apt get autoremove
autoremove is used to remove packages that were automatically installed to satisfy dependencies for some package and no longer needed
8) apt get clean
This command removes the aptitude cache in “/var/cache/apt/archives”,
every time you install a program, the package file is downloaded and stored in that directory.
You don’t need to keep the files in that directory and that what apt-get clean will do removing that files
9) apt get search
To search for a particular package by name or description:
From the command-line, use:
where the search keyword can be all or part of a package name or any words used in its description.
For example, apt-cache search proxy includes both these packages:
tinyproxy - A lightweight, non-caching, optionally anonymizing HTTP proxy
tircd - ircd proxy to the twitter API
Note: the list may be long, so you can pipe the output to less to make it scrollable one line or one screen at a time, i.e. apt-cache search something | less.
--no-install-recommends
Do not consider recommended packages as a dependency for
installing. Configuration Item: APT::Install-Recommends.
-d, --download-only
Download only; package files are only retrieved, not unpacked or
installed. Configuration Item: APT::Get::Download-Only.
-f, --fix-broken
Fix; attempt to correct a system with broken dependencies in place.
This option, when used with install/remove, can omit any packages
to permit APT to deduce a likely solution. If packages are
specified, these have to completely correct the problem. The option
is sometimes necessary when running APT for the first time; APT
itself does not allow broken package dependencies to exist on a
system. It is possible that a system's dependency structure can be
so corrupt as to require manual intervention (which usually means
using dselect(1) or dpkg --remove to eliminate some of the
offending packages). Use of this option together with -m may
produce an error in some situations. Configuration Item:
APT::Get::Fix-Broken.
-m, --ignore-missing, --fix-missing
Ignore missing packages; If packages cannot be retrieved or fail
the integrity check after retrieval (corrupted package files), hold
back those packages and handle the result. Use of this option
together with -f may produce an error in some situations. If a
package is selected for installation (particularly if it is
mentioned on the command line) and it could not be downloaded then
it will be silently held back. Configuration Item:
APT::Get::Fix-Missing.
--no-download
Disables downloading of packages. This is best used with
--ignore-missing to force APT to use only the .debs it has already
downloaded. Configuration Item: APT::Get::Download.
-q, --quiet
Quiet; produces output suitable for logging, omitting progress
indicators. More q's will produce more quiet up to a maximum of 2.
You can also use -q=# to set the quiet level, overriding the
configuration file. Note that quiet level 2 implies -y, you should
never use -qq without a no-action modifier such as -d, --print-uris
or -s as APT may decided to do something you did not expect.
Configuration Item: quiet.
-s, --simulate, --just-print, --dry-run, --recon, --no-act
No action; perform a simulation of events that would occur but do
not actually change the system. Configuration Item:
APT::Get::Simulate.
Simulation run as user will deactivate locking (Debug::NoLocking)
automatic. Also a notice will be displayed indicating that this is
only a simulation, if the option
APT::Get::Show-User-Simulation-Note is set (Default: true). Neither
NoLocking nor the notice will be triggered if run as root (root
should know what he is doing without further warnings by apt-get).
Simulate prints out a series of lines each one representing a dpkg
operation, Configure (Conf), Remove (Remv), Unpack (Inst). Square
brackets indicate broken packages and empty set of square brackets
meaning breaks that are of no consequence (rare).
-y, --yes, --assume-yes
Automatic yes to prompts; assume "yes" as answer to all prompts and
run non-interactively. If an undesirable situation, such as
changing a held package, trying to install a unauthenticated
package or removing an essential package occurs then apt-get will
abort. Configuration Item: APT::Get::Assume-Yes.
-u, --show-upgraded
Show upgraded packages; Print out a list of all packages that are
to be upgraded. Configuration Item: APT::Get::Show-Upgraded.
-V, --verbose-versions
Show full versions for upgraded and installed packages.
Configuration Item: APT::Get::Show-Versions.
-b, --compile, --build
Compile source packages after downloading them. Configuration Item:
APT::Get::Compile.
--install-recommends
Also install recommended packages.
--no-install-recommends
Do not install recommended packages.
--ignore-hold
Ignore package Holds; This causes apt-get to ignore a hold placed
on a package. This may be useful in conjunction with dist-upgrade
to override a large number of undesired holds. Configuration Item:
APT::Ignore-Hold.
--no-upgrade
Do not upgrade packages; When used in conjunction with install,
no-upgrade will prevent packages on the command line from being
upgraded if they are already installed. Configuration Item:
APT::Get::Upgrade.
--force-yes
Force yes; This is a dangerous option that will cause apt to
continue without prompting if it is doing something potentially
harmful. It should not be used except in very special situations.
Using force-yes can potentially destroy your system! Configuration
Item: APT::Get::force-yes.
--print-uris
Instead of fetching the files to install their URIs are printed.
Each URI will have the path, the destination file name, the size
and the expected md5 hash. Note that the file name to write to will
not always match the file name on the remote site! This also works
with the source and update commands. When used with the update
command the MD5 and size are not included, and it is up to the user
to decompress any compressed files. Configuration Item:
APT::Get::Print-URIs.
--purge
Use purge instead of remove for anything that would be removed. An
asterisk ("*") will be displayed next to packages which are
scheduled to be purged. remove --purge is equivalent to the purge
command. Configuration Item: APT::Get::Purge.
--reinstall
Re-Install packages that are already installed and at the newest
version. Configuration Item: APT::Get::ReInstall.
--list-cleanup
This option defaults to on, use --no-list-cleanup to turn it off.
When on apt-get will automatically manage the contents of
/var/lib/apt/lists to ensure that obsolete files are erased. The
only reason to turn it off is if you frequently change your source
list. Configuration Item: APT::Get::List-Cleanup.
-t, --target-release, --default-release
This option controls the default input to the policy engine, it
creates a default pin at priority 990 using the specified release
string. This overrides the general settings in
/etc/apt/preferences. Specifically pinned packages are not affected
by the value of this option. In short, this option lets you have
simple control over which distribution packages will be retrieved
from. Some common examples might be -t '2.1*', -t unstable or -t
sid. Configuration Item: APT::Default-Release; see also the
apt_preferences(5) manual page.
--trivial-only
Only perform operations that are 'trivial'. Logically this can be
considered related to --assume-yes, where --assume-yes will answer
yes to any prompt, --trivial-only will answer no. Configuration
Item: APT::Get::Trivial-Only.
--no-remove
If any packages are to be removed apt-get immediately aborts
without prompting. Configuration Item: APT::Get::Remove.
--auto-remove
If the command is either install or remove, then this option acts
like running autoremove command, removing the unused dependency
packages. Configuration Item: APT::Get::AutomaticRemove.
--only-source
Only has meaning for the source and build-dep commands. Indicates
that the given source names are not to be mapped through the binary
table. This means that if this option is specified, these commands
will only accept source package names as arguments, rather than
accepting binary package names and looking up the corresponding
source package. Configuration Item: APT::Get::Only-Source.
--diff-only, --dsc-only, --tar-only
Download only the diff, dsc, or tar file of a source archive.
Configuration Item: APT::Get::Diff-Only, APT::Get::Dsc-Only, and
APT::Get::Tar-Only.
--arch-only
Only process architecture-dependent build-dependencies.
Configuration Item: APT::Get::Arch-Only.
--allow-unauthenticated
Ignore if packages can't be authenticated and don't prompt about
it. This is useful for tools like pbuilder. Configuration Item:
APT::Get::AllowUnauthenticated.
-h, --help
Show a short usage summary.
-v, --version
Show the program version.
-c, --config-file
Configuration File; Specify a configuration file to use. The
program will read the default configuration file and then this
configuration file. See apt.conf(5) for syntax information.
-o, --option
Set a Configuration Option; This will set an arbitrary
configuration option. The syntax is -o Foo::Bar=bar. -o and
--option can be used multiple times to set different options.
example
You can reinstall a package with apt-get install --reinstall packagename.
This completely removes the package (but not the packages that depend on it) then reinstall's it.
for example if we want to reinstall nmap the command would be like that :
autoremove is used to remove packages that were automatically installed to satisfy dependencies for some package and no longer needed
This command removes the aptitude cache in “/var/cache/apt/archives”,
every time you install a program, the package file is downloaded and stored in that directory.
You don’t need to keep the files in that directory and that what apt-get clean will do removing that files
To search for a particular package by name or description:
From the command-line, use:
where the search keyword can be all or part of a package name or any words used in its description.
For example, apt-cache search proxy includes both these packages:
tinyproxy - A lightweight, non-caching, optionally anonymizing HTTP proxy
tircd - ircd proxy to the twitter API
Note: the list may be long, so you can pipe the output to less to make it scrollable one line or one screen at a time, i.e. apt-cache search something | less.
--no-install-recommends
Do not consider recommended packages as a dependency for
installing. Configuration Item: APT::Install-Recommends.
-d, --download-only
Download only; package files are only retrieved, not unpacked or
installed. Configuration Item: APT::Get::Download-Only.
-f, --fix-broken
Fix; attempt to correct a system with broken dependencies in place.
This option, when used with install/remove, can omit any packages
to permit APT to deduce a likely solution. If packages are
specified, these have to completely correct the problem. The option
is sometimes necessary when running APT for the first time; APT
itself does not allow broken package dependencies to exist on a
system. It is possible that a system's dependency structure can be
so corrupt as to require manual intervention (which usually means
using dselect(1) or dpkg --remove to eliminate some of the
offending packages). Use of this option together with -m may
produce an error in some situations. Configuration Item:
APT::Get::Fix-Broken.
-m, --ignore-missing, --fix-missing
Ignore missing packages; If packages cannot be retrieved or fail
the integrity check after retrieval (corrupted package files), hold
back those packages and handle the result. Use of this option
together with -f may produce an error in some situations. If a
package is selected for installation (particularly if it is
mentioned on the command line) and it could not be downloaded then
it will be silently held back. Configuration Item:
APT::Get::Fix-Missing.
--no-download
Disables downloading of packages. This is best used with
--ignore-missing to force APT to use only the .debs it has already
downloaded. Configuration Item: APT::Get::Download.
-q, --quiet
Quiet; produces output suitable for logging, omitting progress
indicators. More q's will produce more quiet up to a maximum of 2.
You can also use -q=# to set the quiet level, overriding the
configuration file. Note that quiet level 2 implies -y, you should
never use -qq without a no-action modifier such as -d, --print-uris
or -s as APT may decided to do something you did not expect.
Configuration Item: quiet.
-s, --simulate, --just-print, --dry-run, --recon, --no-act
No action; perform a simulation of events that would occur but do
not actually change the system. Configuration Item:
APT::Get::Simulate.
Simulation run as user will deactivate locking (Debug::NoLocking)
automatic. Also a notice will be displayed indicating that this is
only a simulation, if the option
APT::Get::Show-User-Simulation-Note is set (Default: true). Neither
NoLocking nor the notice will be triggered if run as root (root
should know what he is doing without further warnings by apt-get).
Simulate prints out a series of lines each one representing a dpkg
operation, Configure (Conf), Remove (Remv), Unpack (Inst). Square
brackets indicate broken packages and empty set of square brackets
meaning breaks that are of no consequence (rare).
-y, --yes, --assume-yes
Automatic yes to prompts; assume "yes" as answer to all prompts and
run non-interactively. If an undesirable situation, such as
changing a held package, trying to install a unauthenticated
package or removing an essential package occurs then apt-get will
abort. Configuration Item: APT::Get::Assume-Yes.
-u, --show-upgraded
Show upgraded packages; Print out a list of all packages that are
to be upgraded. Configuration Item: APT::Get::Show-Upgraded.
-V, --verbose-versions
Show full versions for upgraded and installed packages.
Configuration Item: APT::Get::Show-Versions.
-b, --compile, --build
Compile source packages after downloading them. Configuration Item:
APT::Get::Compile.
--install-recommends
Also install recommended packages.
--no-install-recommends
Do not install recommended packages.
--ignore-hold
Ignore package Holds; This causes apt-get to ignore a hold placed
on a package. This may be useful in conjunction with dist-upgrade
to override a large number of undesired holds. Configuration Item:
APT::Ignore-Hold.
--no-upgrade
Do not upgrade packages; When used in conjunction with install,
no-upgrade will prevent packages on the command line from being
upgraded if they are already installed. Configuration Item:
APT::Get::Upgrade.
--force-yes
Force yes; This is a dangerous option that will cause apt to
continue without prompting if it is doing something potentially
harmful. It should not be used except in very special situations.
Using force-yes can potentially destroy your system! Configuration
Item: APT::Get::force-yes.
--print-uris
Instead of fetching the files to install their URIs are printed.
Each URI will have the path, the destination file name, the size
and the expected md5 hash. Note that the file name to write to will
not always match the file name on the remote site! This also works
with the source and update commands. When used with the update
command the MD5 and size are not included, and it is up to the user
to decompress any compressed files. Configuration Item:
APT::Get::Print-URIs.
--purge
Use purge instead of remove for anything that would be removed. An
asterisk ("*") will be displayed next to packages which are
scheduled to be purged. remove --purge is equivalent to the purge
command. Configuration Item: APT::Get::Purge.
--reinstall
Re-Install packages that are already installed and at the newest
version. Configuration Item: APT::Get::ReInstall.
--list-cleanup
This option defaults to on, use --no-list-cleanup to turn it off.
When on apt-get will automatically manage the contents of
/var/lib/apt/lists to ensure that obsolete files are erased. The
only reason to turn it off is if you frequently change your source
list. Configuration Item: APT::Get::List-Cleanup.
-t, --target-release, --default-release
This option controls the default input to the policy engine, it
creates a default pin at priority 990 using the specified release
string. This overrides the general settings in
/etc/apt/preferences. Specifically pinned packages are not affected
by the value of this option. In short, this option lets you have
simple control over which distribution packages will be retrieved
from. Some common examples might be -t '2.1*', -t unstable or -t
sid. Configuration Item: APT::Default-Release; see also the
apt_preferences(5) manual page.
--trivial-only
Only perform operations that are 'trivial'. Logically this can be
considered related to --assume-yes, where --assume-yes will answer
yes to any prompt, --trivial-only will answer no. Configuration
Item: APT::Get::Trivial-Only.
--no-remove
If any packages are to be removed apt-get immediately aborts
without prompting. Configuration Item: APT::Get::Remove.
--auto-remove
If the command is either install or remove, then this option acts
like running autoremove command, removing the unused dependency
packages. Configuration Item: APT::Get::AutomaticRemove.
--only-source
Only has meaning for the source and build-dep commands. Indicates
that the given source names are not to be mapped through the binary
table. This means that if this option is specified, these commands
will only accept source package names as arguments, rather than
accepting binary package names and looking up the corresponding
source package. Configuration Item: APT::Get::Only-Source.
--diff-only, --dsc-only, --tar-only
Download only the diff, dsc, or tar file of a source archive.
Configuration Item: APT::Get::Diff-Only, APT::Get::Dsc-Only, and
APT::Get::Tar-Only.
--arch-only
Only process architecture-dependent build-dependencies.
Configuration Item: APT::Get::Arch-Only.
--allow-unauthenticated
Ignore if packages can't be authenticated and don't prompt about
it. This is useful for tools like pbuilder. Configuration Item:
APT::Get::AllowUnauthenticated.
-h, --help
Show a short usage summary.
-v, --version
Show the program version.
-c, --config-file
Configuration File; Specify a configuration file to use. The
program will read the default configuration file and then this
configuration file. See apt.conf(5) for syntax information.
-o, --option
Set a Configuration Option; This will set an arbitrary
configuration option. The syntax is -o Foo::Bar=bar. -o and
--option can be used multiple times to set different options.
The one thing missing here is joing these commands together with &&
ReplyDeleteFor eg:~$#apt-get update && apt-get upgrade && apt-get dist-upgrade
Thank you Yo Yo for your comment :)
Deleteif you would like to write full article and post it here let me know :)