Linux yum powerful basic operations

Do you want to know the truth about the Linux yum system? Do you want to know what is inherent in the Linux yum system, I will only give you a full introduction to the Linux yum system Linux yum after a long period of development. Here I will share my personal understanding. Next I will talk about Linux yum.

What is yum?

Yum is the abbreviation of yellowdog updater modified. Yellowdog is a Linux distribution. RH uses this upgrade technology to build its own distribution to form the current yum. The principle of yum is similar to that of apt, but apt is used to compile code, the execution efficiency is much higher than the yum written in python. This is the home page of yum.

Yum uses a repository to manage the relationship between some or even a distribution application, and upgrades, installs, deletes, and so on based on the calculated software dependency, this reduces the dependencies problem that Linux users have always suffered. At this point, yum and apt are the same. Apt is originally used by deb software management of debian, but now rpm under RH can be used.

Generally, this type of software uses one or more configuration files to describe the corresponding repository network address, obtain necessary information from repository as needed through http or ftp protocol, and download related software packages. In this way, local users can easily perform system upgrade and maintenance when there is an Internet connection by establishing different repository descriptions.

In addition, if you need to use a proxy, you can use http_proxy and ftp_proxy to set the standard environment variables in the shell. The repository is created using the yum-arch or createrepo command. You can also use the existing repository of others as an image. Here we will discuss how to create a repository.

Basic Linux yum operations

Basic Linux yum operations include software installation (local, network), upgrade (local, network), uninstall, and some query functions. After setting the local Linux yum, you can easily install it (now we assume that the yum that comes with fc5 is used for installation). If we need to install the Virtual Machine bochs, you can use # yum install bochs. If there is a related rpm file locally, you can use # yum localinstall ur. rpm causes Linux yum to search for existing data in the repository (usually connected to the repository to download the updated data first). If this software is found, it will analyze its dependencies and then download and install the required software.

If you need to uninstall it, you can use # yum remove bochs or # yum erase bochs, which will also dissolve the corresponding dependencies. If you delete firefox, R will be deleted at the same time, because R relies on firefox to update a software, you can use # yum update firefox. If it does not contain the following program name, all software that can be upgraded will be upgraded. If obsolete software needs to be processed (such as deleted), you can add the -- obsolete parameter or use upgrade.

If you need more automated operations (to avoid answering some questions), you can also add some parameters, such as # yum-y upgrade. If you finish a system-level upgrade, a lot of rpm and other things will be downloaded, this will occupy a lot of hard disks. You can use # yum clean packages to delete the relevant rpm files. Others include headers, packages, cache, metadata, all to see which rpm provides a program that can use $ yum provides/bin/rpm and $ yum list rpm will list rpm-related information, while $ yum list info gives detailed instructions, you can use $ yum search rpm to obtain all rpm-related programs that can be found. The search object is the description of each program.

For more detailed parameter descriptions, see related man pages. In yum-utils, you can find the program named yumdownloader. It can be easily downloaded, such as srpm package $ yumdownloader -- source firefox how to use Linux yum to upgrade my fc? The core part of the upgrade is very simple. First, yum needs to use the new repository. fc also uses an rpm to manage its own version, run the following command to update this package # rpm-Uvh http://download.fedora.redhat.com/pub/fedora\/linux/core/5/i386/OS/Fedora/RPMS/fedora-release-5-5. \ noarch. rpm then uses yum to update fc4-related programs to fc5, # yum-y upgrade

Note that some self-installed programs are not replaced by related repository programs, so it is likely to interfere with this process, such as qterm, which is not in the original repository, the way to be lazy is to first find the relevant repository and add it to the configuration file of Linux yum. The clumsy way is to uninstall these things first... after a long wait (I downloaded 1.5 Gb + stuff that I did), I can watch software updates one by one and then restart the system, the success of using the new kernel boot is almost complete.

Some applications may not be able to process the configuration files of earlier versions. You just need to manually configure the files. My fc5 grew out of fc4 like this ~ The FC has an update FAQ. For more information, see. How to add a new repository in Linux yum? This requires the Linux yum configuration file. Its main configuration file is in/etc/yum. conf. For instructions, refer to here.
The important information is repository. In fc5, the repository information is stored separately, generally in/tec/yum. repos. d/inside, generally a repository written as a file, such as fedora-core.repo.

The repository that provides Linux yum upgrade on the Internet generally provides similar instructions, such as DAG, which provides the rpm for installation. After installation, the Linux yum is configured, you can directly use the following command to execute system maintenance, such as dries, you can create a dries. repo file, the content is [dries] name = Extra Fedora rpms dries-$ releasever-$ basearch baseurl = http://ftp.belnet.be/packages/dries.ulyssis.org/redhat/el3/en/i386/dries this general see understand, will not go into details.

Some other tools

There are also some useful tools in yum-utils, such as package-cleanup for clearing locally installed rpm, and some tools for maintaining repository, such as repo-graph, repo-rss, repoclosure, repomanage, repoquery, reposync, repotrack, yum-builddep.

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