yum

• Yum administrates the rpm packages
• yum downloads rpm files from repositories
• Repositories are stored at: /etc/yum.repos.d
• rpm: Red hat package Manager is the extension file for the binaries
• rpm is used when you have already a package downloaded

# Install package
yum install "package"
yum install "ksh*" # Install everything with ksh keyword

# Uninstall package
yum remove "package"

# Upgrade packages: Install newer version and delete old packages. No rollback allowed!
yum upgrade -y # -y do not prompt for confirm

# Update packages: Install newer version and preserve the old ones. Rollback allowed!
yum update -y

# Clear cache
yum clean all

# List all repos
yum list all

# Yum commands history
yum history

# Undo a specific yum command
yum history undo "id" # If a update command is undone, the package will be downgraded

Local repository

• Repository from DVD are used for environments without internet access
• First remove all the repo list from /etc/yum.repos.d/

• /media/hvitoi/CentOS 7 x86_64/Packages: CentOS rpm packages from official dvd.

• Copy all these packages to any folder e.g. /localrepo

• Create a new local repo local.repo in /etc/yum.repos.d/

[centos7]
name=centos7
baseurl=file:///localrepo/
enabled=1
gpgcheck=0

• Create repo

# Create the repo containing the rpm packages locally
createrepo /localrepo

# Clear cache from the old repository
yum clean all

# List all repos
yum list all