Using the apt Command

Debian based systems (including Ubuntu) uses apt-* commands for managing packages from the command line.

In this article, using Apache 2 installation as an example, let us review how to use apt-* commands to view, install, remove, or upgrade packages.

1. apt-cache search: Search Repository Using Package Name

If you are installing Apache 2, you may guess that the package name is apache2.  To verify whether it is a valid package name, you may want to search the repository for that particular package name as shown below.

The following example shows how to search the repository for a specific package name.

$ apt-cache search ^apache2$
apache2 - Apache HTTP Server metapackage

2. apt-cache search: Search Repository Using Package Description

If you don’t know the exact name of the package, you can still search using the package description as shown below.

$ apt-cache search "Apache HTTP Server"
apache2 - Apache HTTP Server metapackage
apache2-doc - Apache HTTP Server documentation
apache2-mpm-event - Apache HTTP Server - event driven model
apache2-mpm-prefork - Apache HTTP Server - traditional non-threaded model
apache2-mpm-worker - Apache HTTP Server - high speed threaded model
apache2.2-common - Apache HTTP Server common files

3. apt-file search: Search Repository Using a Filename from the Package

Sometimes you may know the configuration file name (or) the executable name from the package that you would like to install.

The following example shows that apache2.conf file is part of the apache2.2-common package. Search the repository with a configuration file name using apt-file command as shown below.

$ apt-file search apache2.conf
apache2.2-common: /etc/apache2/apache2.conf
apache2.2-common: /usr/share/doc/apache2.2-common/examples/apache2/apache2.conf.gz

4. apt-cache show: Basic Information About a Package

Following example displays basic information about apache2 package.

$ apt-cache show apache2
Package: apache2
Priority: optional
Maintainer: Ubuntu Core Developers
Original-Maintainer: Debian Apache Maintainers
Version: 2.2.11-2ubuntu2.3
Depends: apache2-mpm-worker (>= 2.2.11-2ubuntu2.3)
 | apache2-mpm-prefork (>= 2.2.11-2ubuntu2.3)
 | apache2-mpm-event (>= 2.2.11-2ubuntu2.3)
Filename: pool/main/a/apache2/apache2_2.2.11-2ubuntu2.3_all.deb
Size: 46350
Description: Apache HTTP Server metapackage
 The Apache Software Foundation's goal is to build a secure, efficient and
 extensible HTTP server as standards-compliant open source software.
Homepage: http://httpd.apache.org/

5. apt-cache showpkg: Detailed Information About a Package

“apt-cache show” displays basic information about a package. Use “apt-cache showpkg” to display detailed information about a package as shown below.

$ apt-cache showpkg apache2
Package: apache2
Versions:
2.2.11-2ubuntu2.3 (/var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_jaunty-updates_main_binary-i386_Packages) (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_jaunty-security_main_binary-i386_Packages)
 Description Language:
                 File: /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_jaunty-updates_main_binary-i386_Packages
                  MD5: d24f049cd70ccfc178dd8974e4b1ed01
Reverse Depends:
  squirrelmail,apache2
  squid3-cgi,apache2
  phpmyadmin,apache2
  mahara-apache2,apache2
  ipplan,apache2
Dependencies:
  2.2.11-2ubuntu2.3 - apache2-mpm-worker (18 2.2.11-2ubuntu2.3) apache2-mpm-prefork (18 2.2.11-2ubuntu2.3) apache2-mpm-event (2 2.2.11-2ubuntu2.3)
  2.2.11-2ubuntu2 - apache2-mpm-worker (18 2.2.11-2ubuntu2) apache2-mpm-prefork (18 2.2.11-2ubuntu2) apache2-mpm-event (2 2.2.11-2ubuntu2)
Provides:
  2.2.11-2ubuntu2.3 -
  2.2.11-2ubuntu2 -
Reverse Provides:
  apache2-mpm-itk 2.2.6-02-1build4.3
  apache2-mpm-worker 2.2.11-2ubuntu2.3
  apache2-mpm-prefork 2.2.11-2ubuntu2.3
  apache2-mpm-prefork 2.2.11-2ubuntu2
  apache2-mpm-event 2.2.11-2ubuntu2

6. apt-file list: List all the Files Located Inside a Package

Use “apt-file list” to display all the files located inside the apache2 package as shown below.

$ apt-file list apache2 | more
apache2: /usr/share/bug/apache2/control
apache2: /usr/share/bug/apache2/script
apache2: /usr/share/doc/apache2/NEWS.Debian.gz
apache2: /usr/share/doc/apache2/README.Debian.gz
apache2: /usr/share/doc/apache2/changelog.Debian.gz
...

7. apt-cache depends: List all Dependent Packages

Before installation, if you like to view all the dependent packages, use “apt-cache depends” as shown below.

$ apt-cache depends apache2
apache2
 |Depends: apache2-mpm-worker
 |Depends: apache2-mpm-prefork
  Depends: apache2-mpm-event

8. dpkg -l: Is the Package Already Installed?

Before installing a package, you may want to make sure it is not already installed as shown below using dpkg -l command.

$ dpkg -l | grep -i apache

9. apt-get install: Install a Package

Finally, install the package using “apt-get install” as shown below.

$ sudo apt-get install apache2
[sudo] password for ramesh: 

The following NEW packages will be installed:
  apache2 apache2-mpm-worker apache2-utils apache2.2-common libapr1
  libaprutil1 libpq5

0 upgraded, 7 newly installed, 0 to remove and 26 not upgraded.

10. dpkg -l : Verify Whether the Package got Successfully Installed

After installing the package, use “dpkg -l” to make sure it got installed successfully.

$ dpkg -l | grep apache
ii  apache2             2.2.11-2ubuntu2.3  Apache HTTP Server metapackage
ii  apache2-mpm-worker  2.2.11-2ubuntu2.3  Apache HTTP Server - high speed threaded mod
ii  apache2-utils       2.2.11-2ubuntu2.3  utility programs for webservers
ii  apache2.2-common    2.2.11-2ubuntu2.3  Apache HTTP Server common files

11. apt-get remove: Delete a Package

Use “apt-get purge” or “apt-get remove” to delete a package as shown below.

$ sudo apt-get purge apache2

(or)

$ sudo apt-get remove apache2

The following packages were automatically installed and are no longer required:
  apache2-utils linux-headers-2.6.28-11 libapr1 apache2.2-common
  linux-headers-2.6.28-11-generic apache2-mpm-worker libpq5 libaprutil1

Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  apache2
0 upgraded, 0 newly installed, 1 to remove and 26 not upgraded.
Removing apache2 ...
  • apt-get remove will not delete the configuration files of the package
  • apt-get purge will delete the configuration files of the package

12. apt-get -u install: Upgrade a Specific Package

The following example shows how to upgrade one specific package.

$ sudo apt-get -u install apache2
Reading package lists... Done
Building dependency tree
Reading state information... Done
apache2 is already the newest version.
The following packages were automatically installed and are no longer required:
  linux-headers-2.6.28-11 linux-headers-2.6.28-11-generic
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 26 not upgraded.

13. apt-get -u upgrade: Upgrade all Packages

To upgrade all the packages to it’s latest version, use “apt-get -u upgrade” as shown below.

$ sudo apt-get -u upgrade
The following packages will be upgraded:
  libglib2.0-0 libglib2.0-data libicu38 libsmbclient libwbclient0
  openoffice.org-base-core openoffice.org-calc openoffice.org-common
  openoffice.org-core openoffice.org-draw openoffice.org-emailmerge
  openoffice.org-gnome openoffice.org-gtk openoffice.org-impress
  openoffice.org-math openoffice.org-style-human openoffice.org-writer
  python-uno samba-common smbclient ttf-opensymbol tzdata
26 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Using the netstat Command

Netstat command displays various network related information such as network connections, routing tables, interface statistics, masquerade connections, multicast memberships etc.,

In this article, let us review 10 practical unix netstat command examples.

1. List All Ports (both listening and non listening ports)

List all ports using netstat -a

# netstat -a | more
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 localhost:30037         *:*                     LISTEN
udp        0      0 *:bootpc                *:*                                

Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     6135     /tmp/.X11-unix/X0
unix  2      [ ACC ]     STREAM     LISTENING     5140     /var/run/acpid.socket

List all tcp ports using netstat -at

# netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 localhost:30037         *:*                     LISTEN
tcp        0      0 localhost:ipp           *:*                     LISTEN
tcp        0      0 *:smtp                  *:*                     LISTEN
tcp6       0      0 localhost:ipp           [::]:*                  LISTEN

List all udp ports using netstat -au

# netstat -au
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
udp        0      0 *:bootpc                *:*
udp        0      0 *:49119                 *:*
udp        0      0 *:mdns                  *:*

2. List Sockets which are in Listening State

List only listening ports using netstat -l

# netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 localhost:ipp           *:*                     LISTEN
tcp6       0      0 localhost:ipp           [::]:*                  LISTEN
udp        0      0 *:49119                 *:*

List only listening TCP Ports using netstat -lt

# netstat -lt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 localhost:30037         *:*                     LISTEN
tcp        0      0 *:smtp                  *:*                     LISTEN
tcp6       0      0 localhost:ipp           [::]:*                  LISTEN

List only listening UDP Ports using netstat -lu

# netstat -lu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
udp        0      0 *:49119                 *:*
udp        0      0 *:mdns                  *:*

List only the listening UNIX Ports using netstat -lx

# netstat -lx
Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     6294     private/maildrop
unix  2      [ ACC ]     STREAM     LISTENING     6203     public/cleanup
unix  2      [ ACC ]     STREAM     LISTENING     6302     private/ifmail
unix  2      [ ACC ]     STREAM     LISTENING     6306     private/bsmtp

3. Show the statistics for each protocol

Show statistics for all ports using netstat -s

# netstat -s
Ip:
    11150 total packets received
    1 with invalid addresses
    0 forwarded
    0 incoming packets discarded
    11149 incoming packets delivered
    11635 requests sent out
Icmp:
    0 ICMP messages received
    0 input ICMP message failed.
Tcp:
    582 active connections openings
    2 failed connection attempts
    25 connection resets received
Udp:
    1183 packets received
    4 packets to unknown port received.
.....

Show statistics for TCP (or) UDP ports using netstat -st (or) -su

# netstat -st

# netstat -su

4. Display PID and program names in netstat output using netstat -p

netstat -p option can be combined with any other netstat option. This will add the “PID/Program Name” to the netstat output. This is very useful while debugging to identify which program is running on a particular port.

# netstat -pt
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        1      0 ramesh-laptop.loc:47212 192.168.185.75:www        CLOSE_WAIT  2109/firefox
tcp        0      0 ramesh-laptop.loc:52750 lax:www ESTABLISHED 2109/firefox

5. Don’t resolve host, port and user name in netstat output

When you don’t want the name of the host, port or user to be displayed, use netstat -n option. This will display in numbers, instead of resolving the host name, port name, user name.

This also speeds up the output, as netstat is not performing any look-up.

# netstat -an

If you don’t want only any one of those three items ( ports, or hosts, or users ) to be resolved, use following commands.

# netsat -a --numeric-ports

# netsat -a --numeric-hosts

# netsat -a --numeric-users

6. Print netstat information continuously

netstat will print information continuously every few seconds.

# netstat -c
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 ramesh-laptop.loc:36130 101-101-181-225.ama:www ESTABLISHED
tcp        1      1 ramesh-laptop.loc:52564 101.11.169.230:www      CLOSING
tcp        0      0 ramesh-laptop.loc:43758 server-101-101-43-2:www ESTABLISHED
tcp        1      1 ramesh-laptop.loc:42367 101.101.34.101:www      CLOSING
^C

7. Find the non supportive Address families in your system

netstat --verbose

At the end, you will have something like this.

	netstat: no support for `AF IPX' on this system.
	netstat: no support for `AF AX25' on this system.
	netstat: no support for `AF X25' on this system.
	netstat: no support for `AF NETROM' on this system.

8. Display the kernel routing information using netstat -r

# netstat -r
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
192.168.1.0     *               255.255.255.0   U         0 0          0 eth2
link-local      *               255.255.0.0     U         0 0          0 eth2
default         192.168.1.1     0.0.0.0         UG        0 0          0 eth2

Note: Use netstat -rn to display routes in numeric format without resolving for host-names.

9. Find out on which port a program is running

# netstat -ap | grep ssh
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp        1      0 dev-db:ssh           101.174.100.22:39213        CLOSE_WAIT  -
tcp        1      0 dev-db:ssh           101.174.100.22:57643        CLOSE_WAIT  -

Find out which process is using a particular port:

# netstat -an | grep ':80'

10. Show the list of network interfaces

# netstat -i
Kernel Interface table
Iface   MTU Met   RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0       1500 0         0      0      0 0             0      0      0      0 BMU
eth2       1500 0     26196      0      0 0         26883      6      0      0 BMRU
lo        16436 0         4      0      0 0             4      0      0      0 LRU

Display extended information on the interfaces (similar to ifconfig) using netstat -ie:

# netstat -ie
Kernel Interface table
eth0      Link encap:Ethernet  HWaddr 00:10:40:11:11:11
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Memory:f6ae0000-f6b00000

Using the RPM command

RPM command is used for installing, uninstalling, upgrading, querying, listing, and checking RPM packages on your Linux system.

RPM stands for Red Hat Package Manager.

With root privilege, you can use the rpm command with appropriate options to manage the RPM software packages.

In this article, let us review 15 practical examples of rpm command.

Let us take an rpm of Mysql Client and run through all our examples.

1. Installing a RPM package Using rpm -ivh

RPM filename has packagename, version, release and architecture name.

For example, In the MySQL-client-3.23.57-1.i386.rpm file:

  • MySQL-client – Package Name
  • 3.23.57 – Version
  • 1 – Release
  • i386 – Architecture

When you install a RPM, it checks whether your system is suitable for the software the RPM package contains, figures out where to install the files located inside the rpm package, installs them on your system, and adds that piece of software into its database of installed RPM packages.

The following rpm command installs Mysql client package.

# rpm -ivh  MySQL-client-3.23.57-1.i386.rpm
Preparing...                ########################################### [100%]
   1:MySQL-client           ########################################### [100%]

rpm command and options

  • -i : install a package
  • -v : verbose
  • -h : print hash marks as the package archive is unpacked.

You can also use dpkg on Debian, pkgadd on Solaris, depot on HP-UX to install packages.

2. Query all the RPM Packages using rpm -qa

You can use rpm command to query all the packages installed in your system.

# rpm -qa
cdrecord-2.01-10.7.el5
bluez-libs-3.7-1.1
setarch-2.0-1.1
.
.
  • -q query operation
  • -a queries all installed packages

To identify whether a particular rpm package is installed on your system, combine rpm and grep command as shown below. Following command checks whether cdrecord package is installed on your system.

# rpm -qa | grep 'cdrecord'

3. Query a Particular RPM Package using rpm -q

The above example lists all currently installed package. After installation of a package to check the installation, you can query a particular package and verify as shown below.

# rpm -q MySQL-client
MySQL-client-3.23.57-1

# rpm -q MySQL
package MySQL is not installed

Note: To query a package, you should specify the exact package name. If the package name is incorrect, then rpm command will report that the package is not installed.

4. Query RPM Packages in a various format using rpm –queryformat

Rpm command provides an option –queryformat, which allows you to give the header tag names, to list the packages. Enclose the header tag with in {}.

# rpm -qa --queryformat '%{name-%{version}-%{release} %{size}\n'
cdrecord-2.01-10.7 12324
bluez-libs-3.7-1.1 5634
setarch-2.0-1.1 235563
.
.

#

5. Which RPM package does a file belong to? – Use rpm -qf

Let us say, you have list of files and you would want to know which package owns all these files. rpm command has options to achieve this.

The following example shows that /usr/bin/mysqlaccess file is part of the MySQL-client-3.23.57-1 rpm.

# rpm -qf /usr/bin/mysqlaccess
MySQL-client-3.23.57-1
  • -f : file name

6. Locate documentation of a package that owns file using rpm -qdf

Use the following to know the list of documentations, for a package that owns a file. The following command, gives the location of all the manual pages related to mysql package.

# rpm -qdf /usr/bin/mysqlaccess
/usr/share/man/man1/mysql.1.gz
/usr/share/man/man1/mysqlaccess.1.gz
/usr/share/man/man1/mysqladmin.1.gz
/usr/share/man/man1/mysqldump.1.gz
/usr/share/man/man1/mysqlshow.1.gz
  • -d : refers documentation.

7. Information about Installed RPM Package using rpm -qi

rpm command provides a lot of information about an installed pacakge using rpm -qi as shown below:

# rpm -qi MySQL-client
Name        : MySQL-client                 Relocations: (not relocatable)
Version     : 3.23.57                           Vendor: MySQL AB
Release     : 1                             Build Date: Mon 09 Jun 2003 11:08:28 PM CEST
Install Date: Mon 06 Feb 2010 03:19:16 AM PST               Build Host: build.mysql.com
Group       : Applications/Databases        Source RPM: MySQL-3.23.57-1.src.rpm
Size        : 5305109                          License: GPL / LGPL
Signature   : (none)
Packager    : Lenz Grimmer
URL         : http://www.mysql.com/
Summary     : MySQL - Client
Description : This package contains the standard MySQL clients.

If you have an RPM file that you would like to install, but want to know more information about it before installing, you can do the following:

# rpm -qip MySQL-client-3.23.57-1.i386.rpm
Name        : MySQL-client                 Relocations: (not relocatable)
Version     : 3.23.57                           Vendor: MySQL AB
Release     : 1                             Build Date: Mon 09 Jun 2003 11:08:28 PM CEST
Install Date: (not installed)               Build Host: build.mysql.com
Group       : Applications/Databases        Source RPM: MySQL-3.23.57-1.src.rpm
Size        : 5305109                          License: GPL / LGPL
Signature   : (none)
Packager    : Lenz Grimmer
URL         : http://www.mysql.com/
Summary     : MySQL - Client
Description : This package contains the standard MySQL clients.
  • -i : view information about an rpm
  • -p : specify a package name

8. List all the Files in a Package using rpm -qlp

To list the content of a RPM package, use the following command, which will list out the files without extracting into the local directory folder.

$ rpm -qlp ovpc-2.1.10.rpm
/usr/bin/mysqlaccess
/usr/bin/mysqldata
/usr/bin/mysqlperm
.
.
/usr/bin/mysqladmin
  • q : query the rpm file
  • l : list the files in the package
  • p : specify the package name

You can also extract files from RPM package using rpm2cpio as we discussed earlier.

9. List the Dependency Packages using rpm -qRP

To view the list of packages on which this package depends,

# rpm -qRp MySQL-client-3.23.57-1.i386.rpm
/bin/sh
/usr/bin/perl

10. Find out the state of files in a package using rpm -qsp

The following command is to find state (installed, replaced or normal) for all the files in a RPM package.

# rpm -qsp MySQL-client-3.23.57-1.i386.rpm
normal        /usr/bin/msql2mysql
normal        /usr/bin/mysql
normal        /usr/bin/mysql_find_rows
normal        /usr/bin/mysqlaccess
normal        /usr/bin/mysqladmin
normal        /usr/bin/mysqlbinlog
normal        /usr/bin/mysqlcheck
normal        /usr/bin/mysqldump
normal        /usr/bin/mysqlimport
normal        /usr/bin/mysqlshow
normal        /usr/share/man/man1/mysql.1.gz
normal        /usr/share/man/man1/mysqlaccess.1.gz
normal        /usr/share/man/man1/mysqladmin.1.gz
normal        /usr/share/man/man1/mysqldump.1.gz
normal        /usr/share/man/man1/mysqlshow.1.gz

11. Verify a Particular RPM Package using rpm -Vp

Verifying a package compares information about the installed files in the package with information about the files taken from the package metadata stored in the rpm database. In the following command, -V is for verification and -p option is used to specify a package name to verify.

# rpm -Vp MySQL-client-3.23.57-1.i386.rpm
S.5....T c        /usr/bin/msql2mysql
S.5....T c        /usr/bin/mysql
S.5....T c        /usr/bin/mysql_find_rows
S.5....T c        /usr/bin/mysqlaccess

The character in the above output denotes the following:

  • S file Size differs
  • M Mode differs (includes permissions and file type)
  • 5 MD5 sum differs
  • D Device major/minor number mismatch
  • L readlink(2) path mismatch
  • U User ownership differs
  • G Group ownership differs
  • T mTime differs

12. Verify a Package Owning file using rpm -Vf

The following command verify the package which owns the given filename.

# rpm -Vf /usr/bin/mysqlaccess
S.5....T c /usr/bin/mysql
#

13. Upgrading a RPM Package using rpm -Uvh

Upgrading a package is similar to installing one, but RPM automatically un-installs existing versions of the package before installing the new one. If an old version of the package is not found, the upgrade option will still install it.

# rpm -Uvh MySQL-client-3.23.57-1.i386.rpm
Preparing... 			########################################### [100%]
1:MySQL-client          ###########################################

14. Uninstalling a RPM Package using rpm -e

To remove an installed rpm package using -e as shown below. After uninstallation, you can query using rpm -qa and verify the uninstallation.

# rpm -ev MySQL-client

15. Verifying all the RPM Packages using rpm -Va

The following command verifies all the installed packages.

# rpm -Va
S.5....T c /etc/issue
S.5....T c /etc/issue.net
S.5....T c /var/service/imap/ssl/seed
S.5....T c /home/httpd/html/horde/ingo/config/backends.php
.
.
S.5....T c /home/httpd/html/horde/ingo/config/prefs.php
S.5....T c /etc/printcap