Linux applications installed (generally) as packages. Packages contain required files like binary, configuration, database, data, graphic, etc. All files packaged to one file named rpm. There is a lot of packages in fedora or other rpm based distribution to manage.

Keep in mind that there is also a different version of packages like a1,a2,a3. Packages are named like wireshark-1.10.7-3.fc20.x86_64. Here Wireshark is package real name as we know, 1.10.7-3 is the version number used in Wireshark, fc20  shows that this packages used in fedora core 20 but it is not must you can use this packet if you supply dependencies of package, latest x86_64 means that this package includes 64 bit binaries and this is important because it will not work with 32 bit libraries or OS if you see noarch it means that there is no architecture-specific binary. Do we look at all of these things when installing applications? NO, because a lot of work is done by yum rpm manager. Yum, use rpm to make things more smooth and easy. So we just write package name and it installs it.

Install A Package

Installing a package is very easy you can add more packages with space delimiter. Here we will install Wireshark core package and GCC which is a c compiler. If we want to install them without answering yes/no question we must provide -y between yum and install like yum -y install. Here yum resolves dependencies and show installation required packages. There is 9 required package.

$ yum install wireshark gcc

Install A Package From Specified Repository

As we will see below yum can use multiple repositories and the same package can be provided from multiple repositories. While installing this package we can specify specific repository like below.

$ yum --enablerepo="centosplus/7/x86_64"_64 install  tmux

Automatic Confirmation / Yes

While operating with yum commands for caution reasons confirmations exist. If we are confident what we do we simply provide -y parameter to accept all confirmation questions like below.

$ sudo yum install tmux -y

Install Group Packages

If we want to install group which includes a group of packages for similar targets like gnome desktop, KDE desktop, etc. we can use @ sign before package name

$ sudo yum install @"KDE Plasma Workspaces"

Search Package

To search packages with specific word use search. If you want to search all areas of package description use all parameter.

$ yum search wiresh

Search More Details

Name and summary matches only, use “search all” for everything.

$ yum search all wiresh

List Packages

If you want to list all available packages use list option. But there may be a lot of output you can filter it with grep

$ yum list

Update Packages

To update packages use an update. You can specify version if not it is updated to the latest. If not installed it is installed. To see any updates available use check-update which outputs updated packages count. The upgrade is the same but looks for the obsolete flag.

$ sudo yum update

List Group Packages

Repositories provide packages. There can be more than one repository configured in a Linux system. Packages provided configured repositories can be listed like below.

$ yum grouplist

List Installed Group Packages

There is an option to the only list installed group packages.

$ yum grouplist installed

Remove Package

To remove packages use to remove or erase which removes all files and dependencies.

$ sudo yum remove wireshark

Remove Group Packages

Group packages can be removed like a regular package. To remove group packages just provide groupremove like below.

$ sudo yum groupremove "GNOME Desktop"

Find Package Name With File Path

If you want to search a filename in packages use provides or whatprovides. This is a very handy option for looking at what file belongs to what package. Here we query /etc/grub2.cfg and get results from different versions of grub.

$ yum whatprovides /etc/grub2.cfg

Package Information

To get info about a package use info. Wireshark has two packages for x64 and x86 which is shown i686. This will provide information like name, architecture, version, release, size, repository, description, license

$ yum info wireshark

Clean Cache

To clear cache files and get more free space. We can use this command for every 1-2 months. This option has parameters but using all is most practical usage.

$ sudo yum clean all

Yum Interactive Shell

Yum, the shell is used for batch or interactive command line if you specify file the yum commands in the file are executed if not you will get a shell to run yum commands.

$ sudo yum shell

Reinstall Package

Installed packages can be installed again. This will reconfigure the package and clean the binaries and configuration of the package.

$ sudo yum reinstall wireshark

Downgrade Package

This is a rare situation. Packages can be downgraded which means installing older versions. If there is an application relies on old releases this feature can be used. To downgrade a package exact version must be exist configured repository.

$ sudo yum downgrade qemu-img-1.6.2-5.fc20.x86_64

List Package Dependencies

Dependency is the requirement to install a package. A package dependency is another package like libraries, binaries, frameworks. The dependency of a package can be got by providing the package name like below.

$ yum deplist wireshark

List Enabled Repositories

Generally, Linux systems are configured to use more than one repository. There are also popular repositories provided by third parties. All these repositories can be listed with repolist command.

$ yum repolist

List All Repositories

By default yum repolist command provides enabled repositories. There may be some repositories not enabled and not used. Providing all will list all enabled and not enabled repositories.

$ yum repolist all

Print Detailed Repository Information

In the previous example, we have listed repositories. Details about these repositories can be listed with repoinfo command.

$ yum repoinfo base/7/x86_64

repoinfo provides repository information like repository id, name, status, revision, package count, size, mirrors, base URL, expire and file name.

Yum Command History

Yum provides a practical way to see the history of yum with history parameter. To see yum history we can also look to the /var/log/yum.log for more detailed info. history command provides command id, command, issued date and time, action and changed package count.

$ sudo yum history

Resume Transaction

Think about this while installing packages with yum the ssh connection is lost. What will happen can we resume from where we left? Yes. Some times there is an error or disrupt and you need to resume the transaction.

$ sudo yum load-transaction /tmp/yum_save_tx.2017-01-12.13-02.LIA7DG.yumtx

Yum Database Integrity Check

check command will check the status of the yum database. If it founds some corruption it will try to recover this.

$ yum check

Yum Configuration File

Generally yum configuration resides /etc/yum.conf and /etc/yum.conf.d and these paths are used as default. If you want to specify different yum configuration file use -c option

$ yum -c yum.conf search wiresha

Verbose Mode

While using operation commands with yum we may want to get more informed about running the command. We can use -v option to see more details about yum operations.

$ yum -v search wiresha

Install Without GPG/Digest Check

Rpm files are signed for security reasons but some times it may be a trivial problem and we want to disable signature checking use --nogpgcheck. But generally, do not prefer using this option which will provide some security thread for the installed packages.

$ sudo yum install --nogpgcheck tmux

Skip Broken Packages For Update

Sometimes updates come with broken dependencies or packages so you can skip all of them and install other packages without problem use –skip-broken

$ sudo yum --skip-broken update

Only Download Package

To just download packages not install them you can install them later. This will download package to the current working directory like a name tmux-1.8-4.el7.x86_64.rpm

$ sudo yum --downloadonly install tmux