J
Jarret W. Buse
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Linux+: Applications 04 – Yum Introduction
Now that we have covered the use of “rpm” for Red Hat Systems, we need to go over the “yum” utility. The “yum” utility is a command-line program used to download the packages you need and then call “rpm” to perform one of its five modes on the package.
NOTE: For those who may know more about Debian systems, “yum” is the same in nature as “apt”.
To use “yum”, you must have superuser privileges since it could make changes to the system.
The “yum” utility can provide secure connections by using GNU Privacy Guard (GPG), or GnuPG. GPG provides signature verification on packages when it is enabled. GPG can be enabled for all repositories or only specific ones which are used by the Operating System (OS). Any signature verification which is incorrect will not be installed. You are assured that the package being downloaded can be trusted and has not been changed. Changed packages could cause your system harm.
To configure “yum” for GPG, the configuration file is located at /etc/yum.conf. The file has a section called “[main]” which is mandatory to be included in the file. Under the “[main]” section is a line starting with “gpgcheck=value”. The value is either a “0” or “1”. When the value is a “0”, then GPG is disabled. If the value is a “1”, the GPG is enabled.
NOTE: This is a global setting for all repositories. The option can be set individually under each repository entry.
The “rpm” Repositories are locations which contain “rpm” packages. Repositories can be added to the existing list to allow for more places to be searched for packages. The repository list is kept in the /etc/yum.conf file under its own section called “[repository]”. The repository can be added as a .repo file in the folder /etc/yum.repos.d/ which is read by “yum” when a repository list is needed.
NOTE: Adding unknown or untrusted repositories can pose a security risk and should not be done.
Under the [repository] sections are two required entries. The entries are “name=” and “baseurl=”. The “name” entry is a readable name for the repository
Once the .repo file is made, the file can be added by the command “yum-config-manager --add-repo repository_url”. The “repository_url” is the link to the .repo file. For example, an entry could be as follows:
[red-hat-additions-rpms]
name=Red Hat Linux Additional Packages
baseurl= https://cdn.redhat.com/content/dist.../$releasever/$basearch/additions/source/SRPMS
enabled=1
gpgcheck=0
Another option here is the “enabled=” entry is used to enable the repository to be used.
Another entry used in the “[main]” section of yum.conf is “plugins=”. If plugins are to be enabled then set the entry equal to “1” (“0” if the option is disabled). By enabling plugins, you can enhance the abilities of “yum”.
Each plugin will have a separate configuration file located in /etc/yum/pluginconf.d/. If you have a plugin called “plugin-a” there should exist a “plugin-1.conf” within the “etc/yum/pluginconf.d” folder. Each plugin configuration file has an entry in the “[main] section labeled “enabled=”. Like the other such entries, the option can be enabled (“1”) or disabled (“0”).
NOTE: If “plugins=0” is set in the “yum.conf” file, then all plugins are disabled even if the entry “enabled=1” is set for a specific plugin.
The basic syntax for “yum is “yum [subcommand] [package]”. Some specific subcommands may require other optional entries, but these will be noted in the specific section in which they are applicable.
Subcommand
autoremove – remove specified packages and any unneeded packages as well
check – check local RPM database for errors
check-update – checks repositories for any available updates
clean – removes cached packages
deplist – lists dependencies for specified package
downgrade – downgrades a package to an earlier version than the one installed
erase – removes package and dependencies from local system
find-repos-of-install – finds repository from which the package was found
fs – prevents language and documents for package to be installed
fssnapshot – lists LVM snapshots
groupinfo – lists information for a package group
groupinstall – install all packages in a specified group
grouplist – list installed and available package groups
help – lists yum command help information
history – list and use previous yum transactions
info – show specified package information
install – install specified package
langavailable – lists available languages
langinfo – lists packages available for languages
langinstall – install package for specific language
langlist – show installed languages
langremove – remove specified language
list – show package name for repositories
localinstall – install package from local system, HTTP or FTP
makecache – download repository information to local cache
needs-restarting – lists processes installed which needs a system reboot
provides – lists packages which contain a queried file
reinstall – reinstall a package (same version)
remove - removes package and dependencies from local system
repoclosure – get list of dependencies which are missing
repoinfo – show installed repository information
repolist – list enabled repositories
repoquery – query repositories and local RPM database
reposync – sync repositories to a local folder
repotrack – download package of all dependencies
repo-pkgs – uses packages in a repository
search – search the name and description of packages for a match
show-installed – list installed packages
swap – removes a package and installs another in its place
upgrade – updates a package even if it is obsolete
update – update one or all installed packages
update-to - update one or all installed packages to a specified version
updateinfo – displays information on package updates not installed
verifytree – verifies consistency of local yum database
yumdb – changes or checks the yum database
yumdownloader – download package to local folder
yum-complete-transaction – attempts to complete a failed yum transaction
This should supply a basic introduction to the use of “yum”. The other articles will cover more specific uses of “yum”.
Now that we have covered the use of “rpm” for Red Hat Systems, we need to go over the “yum” utility. The “yum” utility is a command-line program used to download the packages you need and then call “rpm” to perform one of its five modes on the package.
NOTE: For those who may know more about Debian systems, “yum” is the same in nature as “apt”.
To use “yum”, you must have superuser privileges since it could make changes to the system.
- Install, Upgrade and Remove
- Queries
- Troubleshoot and Maintenance
- Manage Repositories
- Language Pack Management
- Other options
The “yum” utility can provide secure connections by using GNU Privacy Guard (GPG), or GnuPG. GPG provides signature verification on packages when it is enabled. GPG can be enabled for all repositories or only specific ones which are used by the Operating System (OS). Any signature verification which is incorrect will not be installed. You are assured that the package being downloaded can be trusted and has not been changed. Changed packages could cause your system harm.
To configure “yum” for GPG, the configuration file is located at /etc/yum.conf. The file has a section called “[main]” which is mandatory to be included in the file. Under the “[main]” section is a line starting with “gpgcheck=value”. The value is either a “0” or “1”. When the value is a “0”, then GPG is disabled. If the value is a “1”, the GPG is enabled.
NOTE: This is a global setting for all repositories. The option can be set individually under each repository entry.
The “rpm” Repositories are locations which contain “rpm” packages. Repositories can be added to the existing list to allow for more places to be searched for packages. The repository list is kept in the /etc/yum.conf file under its own section called “[repository]”. The repository can be added as a .repo file in the folder /etc/yum.repos.d/ which is read by “yum” when a repository list is needed.
NOTE: Adding unknown or untrusted repositories can pose a security risk and should not be done.
Under the [repository] sections are two required entries. The entries are “name=” and “baseurl=”. The “name” entry is a readable name for the repository
Once the .repo file is made, the file can be added by the command “yum-config-manager --add-repo repository_url”. The “repository_url” is the link to the .repo file. For example, an entry could be as follows:
[red-hat-additions-rpms]
name=Red Hat Linux Additional Packages
baseurl= https://cdn.redhat.com/content/dist.../$releasever/$basearch/additions/source/SRPMS
enabled=1
gpgcheck=0
Another option here is the “enabled=” entry is used to enable the repository to be used.
Another entry used in the “[main]” section of yum.conf is “plugins=”. If plugins are to be enabled then set the entry equal to “1” (“0” if the option is disabled). By enabling plugins, you can enhance the abilities of “yum”.
Each plugin will have a separate configuration file located in /etc/yum/pluginconf.d/. If you have a plugin called “plugin-a” there should exist a “plugin-1.conf” within the “etc/yum/pluginconf.d” folder. Each plugin configuration file has an entry in the “[main] section labeled “enabled=”. Like the other such entries, the option can be enabled (“1”) or disabled (“0”).
NOTE: If “plugins=0” is set in the “yum.conf” file, then all plugins are disabled even if the entry “enabled=1” is set for a specific plugin.
The basic syntax for “yum is “yum [subcommand] [package]”. Some specific subcommands may require other optional entries, but these will be noted in the specific section in which they are applicable.
Subcommand
autoremove – remove specified packages and any unneeded packages as well
check – check local RPM database for errors
check-update – checks repositories for any available updates
clean – removes cached packages
deplist – lists dependencies for specified package
downgrade – downgrades a package to an earlier version than the one installed
erase – removes package and dependencies from local system
find-repos-of-install – finds repository from which the package was found
fs – prevents language and documents for package to be installed
fssnapshot – lists LVM snapshots
groupinfo – lists information for a package group
groupinstall – install all packages in a specified group
grouplist – list installed and available package groups
help – lists yum command help information
history – list and use previous yum transactions
info – show specified package information
install – install specified package
langavailable – lists available languages
langinfo – lists packages available for languages
langinstall – install package for specific language
langlist – show installed languages
langremove – remove specified language
list – show package name for repositories
localinstall – install package from local system, HTTP or FTP
makecache – download repository information to local cache
needs-restarting – lists processes installed which needs a system reboot
provides – lists packages which contain a queried file
reinstall – reinstall a package (same version)
remove - removes package and dependencies from local system
repoclosure – get list of dependencies which are missing
repoinfo – show installed repository information
repolist – list enabled repositories
repoquery – query repositories and local RPM database
reposync – sync repositories to a local folder
repotrack – download package of all dependencies
repo-pkgs – uses packages in a repository
search – search the name and description of packages for a match
show-installed – list installed packages
swap – removes a package and installs another in its place
upgrade – updates a package even if it is obsolete
update – update one or all installed packages
update-to - update one or all installed packages to a specified version
updateinfo – displays information on package updates not installed
verifytree – verifies consistency of local yum database
yumdb – changes or checks the yum database
yumdownloader – download package to local folder
yum-complete-transaction – attempts to complete a failed yum transaction
This should supply a basic introduction to the use of “yum”. The other articles will cover more specific uses of “yum”.
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