Linux Package Managers (RPM and Debian)

Introduction

============

In this post, we will discuss the 2 common package managers in Linux.

They are the following:

1. RPM-based - rpm,yum

2. Debian-based - dpkg,apt-get,dselect,aptitude,apt-cache

RPM

===

Examples of systems that uses RPM-based package managers are Red Hat, Fedora,

and Centos. The "rpm" command is to install packages directly. It doesn't handle

dependency requirements so you need to install the needed packages (if there is

any) before installing the package you want. For example, if you want to install

packageA but it needs packageB, you need to install packageB first before

proceeding with packageA. Here are the common uses of "rpm" command.

Installing/ Upgrading	# installs a package (install only if it doesn't exist) rpm -i # same as the above, but increases verbosity (-v) and hashes as progress # indicator (-h) rpm -ivh # installs a package even if it exists (package reinstall) rpm -ivh --force # freshens a package (upgrade a package if ONLY an older version exists) rpm -Fvh # installs a package if that doesn't exist or upgrade a package if it # exists rpm -Uvh # installs a package ignoring dependency checking (use this with caution # because the program you will install might not work) rpm -ivh --nodeps # do a dry-run instead of installing actual package rpm -i --test
Removing	# removes a package rpm -e
Querying	# queries a package (-q) by printing information (-i); takes only # package name and not filename (file.rpm) rpm -qi # lists files associated in the package (-l) rpm -ql # shows you on what package the file/directory/script came from; example # is rpm -qf $(which cp) rpm -qf # prints change log of the given package rpm -qi --change-log # prints scripts that ran when the package was installed rpm -qi --scripts # queries a package filename instead (-p) of package name; example is # rpm -qip my-program.rpm rpm -q[other query options]p file_name.rpm

YUM

===

There is also an RPM-based tool that handles dependency conflicts automatically

and that is YUM (Yellowdog Updater Modified). "yum" command is the one we used

which can also do what "rpm" command can. This is the best package management

tool to use if you are using the Linux distributions mentioned above.

The main disadvantage of this is you need a repository before you can do any

transactions whereas RPM don't. Repositories are the ones inside

/etc/yum.repos.d directory and will be discussed on a separate post in this

blog. YUM commands that are commonly used are:

Installing/ Upgrading	# installs a package or multiple packages yum install # same as above but answers "y" to all installation questions yum install -y # updates all installed packages on the system yum update # updates a single or multiple packages yum update # installs a local rpm file using your yum repository to resolve # dependencies yum localinstall
Removing	# removes packages and all packages where the package depends on yum remove # same as above yum erase
Querying	# lists all installed packages yum list # searches all package names that contains the string; prints both # installed and available packages yum search *pattern* # deeper search compare to the above command (searches also contents not # only package names) yum search all *pattern* # shows what package owns the file/directory yum provides # use this when you don't get a result from the above command yum whatprovides */ # shows info on a package (similar to rpm -qi) yum info # checks whether there are updates available yum check-update

  

DPKG

====

Aside from RPM-based systems, we also have Debian-based systems. Examples of

these are Ubuntu and of course Debian. The package management tools they use are

apt-get, aptitude, dselect, and dpkg. "apt-get" is similar to yum where you need

a repository which is defined under /etc/apt/sources.lst, "dpkg" is similar to

rpm, "dselect" is a menu based tool, and aptitude is a combination of dselect's

menu based and apt-get's cli features. Debian packages by convention ends with

.deb. Let's start with dpkg. Here are the common commands for dpkg.

Installing/ Upgrading/ Configuring	# installs a package dpkg -i # ignore dependency conflict (similar to --nodeps in rpm) dpgk -i --ignore-depends= # tests for dependency only (similar to --test in rpm) dpkg -i --no-act # doesn't install a package if a newer version of same package is # already installed dpkg -iG # doesn't install a package if same version of package is already # installed dpkg -iE
Removing	# removes a package while retaining its configuration files dpkg -r # removes a package and configuration files dpkg -P
Querying	# displays information about an installed package dpkg -P # displays information about an uninstalled package dpkg -I # displays current installed packages dpkg --get-selections # list installed packages matching the pattern string dpkg -l # lists files associated with the package (similar to rpm -ql) dpkg -L

   

One command that is very useful if you want to return the package to its

original state (fresh install with default settings) is "dpkg-reconfigure".

For example, the command below will reconfigure the samba package, asking the

packages initial installation questions and restarting its daemons.

dpkg-reconfigure samba

APT-GET

=======

Similar to yum , Debian-based systems have the tool called "apt-get" which

automatically handle dependency conflicts. Before using it, make sure you have

the appropriate sources inside /etc/apt/sources.lst. Here are the common usage

of that command:

Installing/ Upgrading	# installs a package apt-get install # installs a package assuming "y" to all questions apt-get install -y # don't upgrade a package if an older version exists apt-get install --no-upgrade # downloads a package but doesn't install it apt-get install -d # performs a simulation/dry-run without installing any package or # configuring any file apt-get install -s # obtains information on available packages inside /etc/apt/sources.lst apt-get update # upgrades all installed packages to newer versions apt-get upgrade # similar to above command but performs "smart" conflict resolution apt-get dist-upgrade
Removing	# removes a package apt-get remove
Configuring	# performs any changes in package status left undone after running # deselect apt-get dselect-upgrade # performs housekeeping (like yum clean) apt-get clean # similar to the above command but removes about packages that can no # longer be downloaded apt-get autoclean
Querying	# checks package database for consistency and broken package # installations apt-get check

  

APT-CACHE

=========

We also have apt-cache. Its only purpose is to provide information about Debian

package database. Here are sample commands:

Listing

# displays information about a package apt-cache showpkg # displays package statistics (how many installed, dependencies recorded # etc..) apt-cache stats # displays information about unmet dependencies apt-cache unmet #  shows on what packages the one you specified depend on apt-cache depends # displays all installed packages apt-cache pkgnames # displays list of installed packages matching the string specified apt-cache pkgnames

DSELECT

=======

A menu-based package manager also exists for Debian-based systems. That is

"dselect". When invoked, it will display you the following menu.

0. [A]ccess Choose the access method to use.

1. [U]pdate Update list of available packages, if possible.

2. [S]elect Request which packages you want on your system.

3. [I]nstall Install and upgrade wanted packages.

4. [C]onfig Configure any packages that are unconfigured.

5. [R]emove Remove unwanted software.

6. [Q]uit Quit dselect.

APTITUDE

========

A tool that combines dselect's menu based gui and apt-get's cli is "aptitude".

Here are the common usage:

Listing/ Querying	# searches packages related to the one you # NOTE: (apt-get seems not to have this feature aptitude search specified # update package list from APT repository aptitude update # shows complete options aptitude help
Installing/ Upgrading	# installs a package aptitude install # upgrades all installed packages aptitude full-upgrade # conservative version of the above command aptitude safe-upgrade # removes already-downloaded packages that are no longer available aptitude autoclean
Removing	# removes a package (w/ leading dash) aptitude install - # same as above aptitude remove