学步园

This article explains how quickly you can learn to install, remove, update and searchsoftware
packages using apt-get and apt-cache commands
from the command line. This article provides some useful commands that will help you to handle package management inDebian/Ubuntu based
systems.

What is apt-get?

The apt-get utility
is a powerful and free package management command line program, that is used to work with Ubuntu’s
APT (Advanced
Packaging Tool) library to perform installation of new software packages, removing existing software packages, upgrading of existing software packages and even used to upgrading the entire operating system.

What is apt-cache?

The apt-cache command
line tool is used for searching apt software package cache. In simple words, this tool is used to search software packages, collects information of packages and also used to search for what available packages are ready for installation on Debian orUbuntu based
systems.

1. How Do I List All Available Packages?

To list all the available packages, type the following command.

$ apt-cache pkgnames

esseract-ocr-epo
pipenightdreams
mumudvb
tbb-examples
libsvm-java
libmrpt-hmtslam0.9
libboost-timer1.50-dev
kcm-touchpad
g++-4.5-multilib
...

2. How Do I Find Out Package Name and Description of Software?

To find out the package name and with it description before installing, use the ‘search‘
flag. Using “search”
with apt-cache will
display a list of matched packages with short description. Let’s say you would like to find out description of package ‘vsftpd‘,
then command would be.

$ apt-cache search vsftpd

vsftpd - lightweight, efficient FTP server written for security
ccze - A robust, modular log coloriser
ftpd - File Transfer Protocol (FTP) server
yasat - simple stupid audit tool

To find and list down all the packages starting with ‘vsftpd‘,
you could use the following command.

$ apt-cache pkgnames vsftpd

vsttpd

3. How Do I Check Package Information?

For example, if you would like to check information of package along with it short description say (version number, check sums, size, installed size, category etc). Use ‘show‘
sub command as shown below.

$ apt-cache show netcat

Package: netcat
Priority: optional
Section: universe/net
Installed-Size: 30
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Ruben Molina <rmolina@udea.edu.co>
Architecture: all
Version: 1.10-40
Depends: netcat-traditional (>= 1.10-39)
Filename: pool/universe/n/netcat/netcat_1.10-40_all.deb
Size: 3340
MD5sum: 37c303f02b260481fa4fc9fb8b2c1004
SHA1: 0371a3950d6967480985aa014fbb6fb898bcea3a
SHA256: eeecb4c93f03f455d2c3f57b0a1e83b54dbeced0918ae563784e86a37bcc16c9
Description-en: TCP/IP swiss army knife -- transitional package
 This is a "dummy" package that depends on lenny's default version of
 netcat, to ease upgrades. It may be safely removed.
Description-md5: 1353f8c1d079348417c2180319bdde09
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu

4. How Do I Check Dependencies for Specific Packages?

Use the ‘showpkg‘
sub command to check the dependencies for particular software packages. whether those dependencies packages are installed or not. For example, use the ‘showpkg‘
command along with package-name.

$ apt-cache showpkg vsftpd

Package: vsftpd
Versions: 
2.3.5-3ubuntu1 (/var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_quantal_main_binary-i386_Packages)
 Description Language: 
                 File: /var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_quantal_main_binary-i386_Packages
                  MD5: 81386f72ac91a5ea48f8db0b023f3f9b
 Description Language: en
                 File: /var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_quantal_main_i18n_Translation-en
                  MD5: 81386f72ac91a5ea48f8db0b023f3f9b

Reverse Depends: 
  ubumirror,vsftpd
  harden-servers,vsftpd
Dependencies: 
2.3.5-3ubuntu1 - debconf (18 0.5) debconf-2.0 (0 (null)) upstart-job (0 (null)) libc6 (2 2.15) libcap2 (2 2.10) libpam0g (2 0.99.7.1) libssl1.0.0 (2 1.0.0) libwrap0 (2 7.6-4~) adduser (0 (null)) libpam-modules (0 (null)) netbase (0 (null)) logrotate (0 (null)) ftp-server (0 (null)) ftp-server (0 (null)) 
Provides: 
2.3.5-3ubuntu1 - ftp-server 
Reverse Provides:

5. How Do I Check statistics of Cache

The ‘stats‘
sub command will display overall statistics about the cache. For example, the following command will display Total package names is the number of packages have found in the cache.

$ apt-cache stats

Total package names: 51868 (1,037 k)
Total package structures: 51868 (2,490 k)
  Normal packages: 39505
  Pure virtual packages: 602
  Single virtual packages: 3819
  Mixed virtual packages: 1052
  Missing: 6890
Total distinct versions: 43015 (2,753 k)
Total distinct descriptions: 81048 (1,945 k)
Total dependencies: 252299 (7,064 k)
Total ver/file relations: 45567 (729 k)
Total Desc/File relations: 81048 (1,297 k)
Total Provides mappings: 8228 (165 k)
Total globbed strings: 286 (3,518 )
Total dependency version space: 1,145 k
Total slack space: 62.6 k
Total space accounted for: 13.3 M

6. How to Update System Packages

The ‘update‘
command is used to resynchronize the package index files from the their sources specified in /etc/apt/sources.list file.
The update command fetched the packages from their locations and update the packages to newer version.

$ sudo apt-get update

[sudo] password for tecmint: 
Ign http://security.ubuntu.com quantal-security InRelease                      
Get:1 http://security.ubuntu.com quantal-security Release.gpg [933 B]          
Get:2 http://security.ubuntu.com quantal-security Release [49.6 kB]            
Ign http://in.archive.ubuntu.com quantal InRelease                             
Ign http://in.archive.ubuntu.com quantal-updates InRelease                     
Get:3 http://repo.varnish-cache.org precise InRelease [13.7 kB]                
Ign http://in.archive.ubuntu.com quantal-backports InRelease                   
Hit http://in.archive.ubuntu.com quantal Release.gpg                           
Get:4 http://security.ubuntu.com quantal-security/main Sources [34.8 kB]       
Get:5 http://in.archive.ubuntu.com quantal-updates Release.gpg [933 B]         
...

7. How to Upgrade Software Packages

The ‘upgrade‘
command is used to upgrade all the currently installed software packages on the system. Under any circumstances currently installed packages are not removed or packages which are not already installed neither retrieved and installed to satisfy upgrade dependencies.

$ sudo apt-get upgrade

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages have been kept back:
  linux-headers-generic linux-image-generic wine1.5 wine1.5-i386
The following packages will be upgraded:
  activity-log-manager-common activity-log-manager-control-center adium-theme-ubuntu alacarte
  alsa-base app-install-data-partner appmenu-gtk appmenu-gtk3 apport apport-gtk apt
  apt-transport-https apt-utils aptdaemon aptdaemon-data at-spi2-core bamfdaemon base-files bind9-host
   ...

However, if you want to upgrade, unconcerned of whether software packages will be added or removed to fulfill dependencies, use the ‘dist-upgrade‘
sub command.

$ sudo apt-get dist-upgrade

8. How Do I Install or Upgrade Specific Packages?

The ‘install‘
sub command is tracked by one or more packages wish for installation or upgrading.

$ sudo apt-get install netcat

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  netcat-traditional
The following NEW packages will be installed:
  netcat netcat-traditional
0 upgraded, 2 newly installed, 0 to remove and 328 not upgraded.
Need to get 67.1 kB of archives.
After this operation, 186 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://in.archive.ubuntu.com/ubuntu/ quantal/universe netcat-traditional i386 1.10-40 [63.8 kB]
Get:2 http://in.archive.ubuntu.com/ubuntu/ quantal/universe netcat all 1.10-40 [3,340 B]
Fetched 67.1 kB in 1s (37.5 kB/s)
Selecting previously unselected package netcat-traditional.
(Reading database ... 216118 files and directories currently installed.)
Unpacking netcat-traditional (from .../netcat-traditional_1.10-40_i386.deb) ...
Selecting previously unselected package netcat.
Unpacking netcat (from .../netcat_1.10-40_all.deb) ...
Processing triggers for man-db ...
Setting up netcat-traditional (1.10-40) ...
Setting up netcat (1.10-40) ...

9. How I can Install Multiple Packages?

You can add more than one package name along with the command in order to install multiple packages at the same time. For example, the following command will install packages ‘nethogs‘
and ‘goaccess‘.

$ sudo apt-get install nethogs goaccess

Reading package lists... Done
Building dependency tree       
Reading state information... Done
goaccess is already the newest version.
nethogs is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 328 not upgraded.

10. How to Install Several Packages using Wildcard

With the help of regular expression you can add several packages with one string. For example, we use * wildcard
to install several packages that contains the ‘*name*‘
string, name would be ‘package-name’.

$ sudo apt-get install '*name*'

11. How to install Packages without Upgrading

Using sub ‘–no-upgrade‘
command will prevent already installed packages from upgrading.

$ sudo apt-get install packageName --no-upgrade

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Skipping vsftpd, it is already installed and upgrade is not set.
0 upgraded, 0 newly installed, 0 to remove and 328 not upgraded.

12. How to Upgrade Only Specific Packages

The ‘–only-upgrade‘
command do not install new packages but it only upgrade the already installed packages and disables new installation of packages.

$ sudo apt-get install packageName --only-upgrade

Reading package lists... Done
Building dependency tree       
Reading state information... Done
vsftpd is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 328 not upgraded.

13. How Do I Install Specific Package Version?

Let’s say you wish to install only specific version of packages, simply use the ‘=‘
with the package-name and append desired version.

$ sudo apt-get install vsftpd=2.3.5-3ubuntu1

Reading package lists... Done
Building dependency tree       
Reading state information... Done
vsftpd is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 328 not upgraded.

14. How Do I Remove Packages Without Configuration

To un-install software packages without removing their configuration files (for later re-use the same configuration). Use the ‘remove‘
command as shown.

$ sudo apt-get remove vsftpd

[sudo] password for tecmint: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  vsftpd
0 upgraded, 0 newly installed, 1 to remove and 328 not upgraded.
After this operation, 364 kB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 216156 files and directories currently installed.)
Removing vsftpd ...
vsftpd stop/waiting
Processing triggers for ureadahead ...
Processing triggers for man-db ...

15. How Do I Completely Remove Packages

To remove software packages including their configuration files, use the ‘purge‘
sub command as shown below.

$ sudo apt-get purge vsftpd

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  vsftpd*
0 upgraded, 0 newly installed, 1 to remove and 328 not upgraded.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? y
(Reading database ... 216107 files and directories currently installed.)
Removing vsftpd ...
Purging configuration files for vsftpd ...
Processing triggers for ureadahead ...

Alternatively, you can combine both the commands together as shown below.

$ sudo apt-get remove --purge vsftpd

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  vsftpd*
0 upgraded, 0 newly installed, 1 to remove and 328 not upgraded.
After this operation, 364 kB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 216156 files and directories currently installed.)
Removing vsftpd ...
vsftpd stop/waiting
Purging configuration files for vsftpd ...
Processing triggers for ureadahead ...
Processing triggers for man-db ...

16. How I Can Clean Up Disk Space

The ‘clean‘
command is used to free up the disk space by cleaning retrieved (downloaded).deb files
(packages) from the local repository.

$ sudo apt-get clean

17. How Do I Download Only Source Code of Package

To download only source code of particular package, use the option ‘–download-only
source‘ with ‘package-name’ as shown.

$ sudo apt-get --download-only source vsftpd

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Need to get 220 kB of source archives.
Get:1 http://in.archive.ubuntu.com/ubuntu/ quantal/main vsftpd 2.3.5-3ubuntu1 (dsc) [1,883 B]
Get:2 http://in.archive.ubuntu.com/ubuntu/ quantal/main vsftpd 2.3.5-3ubuntu1 (tar) [188 kB]
Get:3 http://in.archive.ubuntu.com/ubuntu/ quantal/main vsftpd 2.3.5-3ubuntu1 (diff) [30.5 kB]
Fetched 220 kB in 4s (49.1 kB/s)
Download complete and in download only mode

18. How Can I Download and Unpack a Package

To download and unpack source code of a package to a specific directory, type the following command.

$ sudo apt-get source vsftpd

Reading package lists... Done

Building dependency tree

Reading state information... Done

Need to get 220 kB of source archives.

Get:1 http://in.archive.ubuntu.com/ubuntu/ quantal/main vsftpd 2.3.5-3ubuntu1 (dsc) [1,883 B]

Get:2 http://in.archive.ubuntu.com/ubuntu/ quantal/main vsftpd 2.3.5-3ubuntu1 (tar) [188 kB]

Get:3 http://in.archive.ubuntu.com/ubuntu/ quantal/main vsftpd 2.3.5-3ubuntu1 (diff) [30.5 kB]

Fetched 220 kB in 1s (112 kB/s)

gpgv: Signature made Thursday 24 May 2012 02:35:09 AM IST using RSA key ID 2C48EE4E

gpgv: Can't check signature: public key not found

dpkg-source: warning: failed to verify signature on ./vsftpd_2.3.5-3ubuntu1.dsc

dpkg-source: info: extracting vsftpd in vsftpd-2.3.5

dpkg-source: info: unpacking vsftpd_2.3.5.orig.tar.gz

dpkg-source: info: unpacking vsftpd_2.3.5-3ubuntu1.debian.tar.gz

dpkg-source: info: applying 01-builddefs.patch

dpkg-source: info: applying 02-config.patch

dpkg-source: info: applying 03-db-doc.patch

dpkg-source: info: applying 04-link-local.patch

dpkg-source: info: applying 05-whitespaces.patch

dpkg-source: info: applying 06-greedy.patch

dpkg-source: info: applying 07-utf8.patch

dpkg-source: info: applying 08-manpage.patch

dpkg-source: info: applying 09-s390.patch

dpkg-source: info: applying 10-remote-dos.patch

dpkg-source: info: applying 11-alpha.pa