First, yum principle:
1) Yum Introduction:
Yum (full name Yellow Dog Updater, Modified) is a shell front-end package manager in Fedora and Redhat as well as SuSE and CentOS.
2) The role of Yum:
Yum's mission is to automate upgrades, install/remove RPM packages, collect information about RPM packages, check dependencies, and automatically prompt users to resolve them.
3) Characteristics of Yum:
1, yum can automatically download the RPM package from the designated server, and install;
2, Yum can automatically deal with the dependencies between the software package;
3, yum can install all the dependent software packages at a one-time, without tedious download, installation;
4. Simple configuration (/etc/yum.conf,/etc/yum.repo.d/youname.repo)
5. Easy to use
4) related information about the Yum configuration:
Yum All configuration information is stored in the/etc/yum.conf configuration file, this file is the most important of the entire Yum system, so it is necessary to explain in detail.
5) Yum Warehouse:
Yum The default warehouse is placed in the/ETC/YUM/REPOS.D directory;
The file system which is placed in the/ETC/YUM/REPOS.D directory, with the. Repo suffix, will be identified as the Yum warehouse file;
Yum Warehouse is the key point of Yum, Yum need to have reliable repository;
Warehouses can be HTTP or FTP sites, or local warehouses, but must include RPM's header,header including a variety of information about the RPM package, including descriptions, functions, provided files, dependencies, etc.
It is by collecting these headers and analyzing them that the remaining tasks can be done automatically.
6) Yum Related configuration command:
(1), RPM package update
* Check for updatable RPM packages
#yum check-update
* Update all RPM packages
#yum Update
* Update the specified RPM package, such as update kernel and kernel source
#yum Update Kernel Kernel-source
* Large-scale version upgrades, unlike Yum Update, even old obsolete packages are upgraded
#yum Upgrade
(2), the installation and removal of RPM package
* Install RPM packages, such as Xmms-mp3
#yum Install Xmms-mp3
* Delete the RPM package, including a dependent package with the package
#yum Remove Licq
* Note: At the same time will be prompted to delete Licq-gnome,licq-qt,licq-text