Yum how does it work

Log in to comment. BQ Newbie 7 points. Bruno Queiros. Can i translate this to Portuguese and can you make it available? RW Newbie 7 points. Roy WiSe. If the name starts with an character the rest of the name is used as though passed to the groupinstall command. If the name is a file, then install works like localinstall. Also note that for filelists, wildcards will match multiple packages. If one or more packages or package globs are specified, Yum will only update the listed packages.

While updating packages, yum will ensure that all dependencies are satisfied. If the packages or globs specified match to packages which are not currently installed then update will not install them.

If the main obsoletes configure option is true default or the --obsoletes flag is present yum will include package obsoletes in its calculations - this makes it better for distro-version changes, for example: upgrading from somelinux 8. Returns exit value of if there are packages available for an update. Also returns a list of the pkgs to be updated in list format.

Returns 0 if no packages are available for update. Returns 1 if an error occurred. Running in verbose mode also shows obsoletes. See update for more details. Just use a specific name or a file-glob-syntax wildcards to list the packages available or installed that provide that feature or file.

Useful for finding a package you do not know by name but know by some word related to it. More complete details can be found in the Clean Options section below. The optional "hidden" argument will also list groups marked as not being "user visible".

It is worth pointing out that packages can be in more than one group, so "groupinstall X Y" followed by "groupremove Y" does not do give you the same result as "groupinstall X". See yum-shell 8 for more info resolvedep Is used to list packages providing the specified dependencies, at most one package is listed per dependency. If required the enabled repositories will be used to resolve dependencies. Note that the install command will do a local install, if given a filename.

Only the specified rpm files of which an older version is already installed will be installed, the remaining specified packages will be ignored. Note that the update command will do a local install, if given a filename. This does not work for "installonly" packages, like Kernels.

The depsolver will not necessarily work, but if you specify all the packages it should work and thus. Also this does not work for "installonly" packages, like Kernels. The default is to list all enabled repositories. If you pass -v, for verbose mode, more information is listed. Tag Description -h, --help Help; display a help message and then quit. Configuration Option: assumeyes -c [config file] Specifies the config file location - can take http, ftp urls and local file paths. Note that you likely also want to use -y.

Practical range: 0 - 10 Configuration Option: debuglevel -e [number] Sets the error level to [number] Practical range 0 - Configuration Option: errorlevel -R [time in minutes] Sets the maximum amount of time yum will wait before performing a command - it randomizes over the time. Configuration Option: enabled --obsoletes This option only has affect for an update, it enables yum 's obsoletes processing logic.

For more information see the update command above. Note that some commands Eg. Configuration Option: plugins --nogpgcheck Run with gpg signature checking disabled. An installer or program manager, must handle those overhead by itself by not harassing the user. Linux, by nature is the best operating system out there if you configured it the right way.

The main issue with installing a program's in Linux distribution's is the fact that, different distribution's use different methods to install a program. Here, in this post we will be discussing a very famous tool used to install program's in Red Hat Linux system's even fedora,centos and all red hat like system's.

That's none other than the very famous YUM. Like all other program's in Linux, YUM is also an open source tool. It was initially used in Duke University, for managing package installation on their Red Hat based system's. These day's its been widely used by almost all Red Hat based system's. In fact its the default program installer and package management tool these days.

If you are interested in visiting the official home page of YUM, then i would recommend, visiting the below link of Duke university. A Linux software package is nothing but a compressed archive of files,consisting of a particular product information,program files,icons,libraries etc.

All required files of an application is compiled in a single file format called with a file extension of. The Red Hat package manager tool, which is installed in all RPM based system, knows how to open and install these. RPM itself is a vast topic, so we will be covering that in separate post, in great detail. RPM is the package manager tool which installs the package. YUM is a repository management tool which will fetch the appropriate package for your particular version of Linux along with all other required packages.

Repositories is an organized collection of packages that YUM uses. YUM can use these repositories to fetch the correct and exact version of a particular package compatible for your system. Previously before YUM or before the existence of such repository management tools , the user had to fetch the rpm package for installation, and if a dependency problem arises, the user had to fetch those dependencies from internet or some other sources.

You can in fact update all the installed applications on your system, with the help of a single YUM command yum will fetch different packages from appropriate different repositories. However all are not installed, when you install the operating system. Later on if you need a particular package, its not at all advisable to insert the installation disk once again, and fetch that required.

Again if you face dependency problems, you need to fetch that dependency package once again sometimes there are yet another dependency package required for installing your dependency package. So it becomes a tedious job. Let's go through a step by step method of creating a local YUM repository.

Step 1: Copy all the. Step 2: For showing you this example, i will be copying all the. If you see the above output there are around packages in the installation disk, i have not shown the whole output.

As i told before, a repository is nothing but a collection of packages in a directory. YUM was made, so that an operating system can use different repositories at the same time. It is not at all feasible for an operating system to download the entire repository because a repository is sometimes very large in the size of Gigabytes.

And YUM was designed to fetch and download only those packages that are required to install your required software on demand. For example, if i want to install a package called "Perl" , YUM must first have the list of all the package's in a repository note the fact that it only requires the list, not the package. YUM will download the total list of packages available in a repository the list will contain the package names in the repository,package details etc.

Not that it will download only the list of packages with details, not the packages. After downloading the list, If yum was able to fetch all the dependencies for your required package from that repository or other repositories yum will install it after confirming with you.

Now lets make that file, which will be containing the package names and other repository details. For this, there is another tool called "Createrepo". Let's see what createrepo does. After running "createrepo" for our repository directory you will have an extra directory along with the packages inside the repository. You can clearly see there are four files inside that directory. Let's understand the contents of each and every file in detail.

Let's see what's inside that compressed file with the help of "zcat". For explanation i have copied one line from the file "filelists. If you see the above line, the first entry tell's the package ID, which will uniquely identify the package. The second entry "name" ofcourse suggests the name of the package.

An important fact to note is that, it also gives the information about the file's that are going to be installed on the system, if you install this package.