Installing, updating and removing software with DNF

Do these on your own system. They get harder. Check each result, then tick it off.

1. Warm-upDone

   Find a package and read about it

   Search the repositories for a package that provides the tree command, show its details and say which repository it comes from.

   Check your result

   dnf info tree shows Name, Version, Repository (for example rhel-10-for-x86_64-appstream-rpms or appstream) and Summary.

   Hint

   dnf search tree, dnf info tree, or dnf provides /usr/bin/tree.

   Solution

   dnf search tree | head
   dnf info tree
   dnf provides /usr/bin/tree

2. PracticeDone

   Install, use, remove

   Install tree non-interactively. Confirm with rpm -q. Remove it and confirm it is gone. Explain what -y does and why you should read the transaction summary first when not using it.

   Check your result

   rpm -q tree shows a version after install, and package tree is not installed after removal.

   Hint

   sudo dnf install -y tree, sudo dnf remove -y tree.

   Solution

   sudo dnf install -y tree
   rpm -q tree
   tree -L 1 /etc | head -5
   sudo dnf remove -y tree
   rpm -q tree

3. PracticeDone

   Install a downloaded RPM file

   Download the RPM for tree into ~/lab/rpms (dnf download), then install from the file using DNF so that any dependencies would be resolved from the repositories. Do not use rpm -ivh. Remove it again.

   Check your result

   rpm -q tree shows it installed after sudo dnf install ./tree-*.rpm.

   Hint

   Give dnf install a path that contains a slash, like ./file.rpm; otherwise it searches repositories for a package of that name.

   Solution

   mkdir -p ~/lab/rpms && cd ~/lab/rpms
   dnf download tree
   sudo dnf install -y ./tree-*.rpm
   rpm -q tree
   sudo dnf remove -y tree

4. PracticeDone

   See what needs updating

   List the packages for which updates are available, show only security updates, then update a single package (tzdata or any package that is listed) without touching the rest of the system.

   Check your result

   dnf check-update exits with 100 when updates exist. dnf upgrade -y tzdata changes only that package (and anything it requires).

   Hint

   dnf check-update, dnf updateinfo list security, dnf upgrade PACKAGE.

   Solution

   dnf check-update; echo "exit=$?"
   dnf updateinfo list security | head
   sudo dnf upgrade -y tzdata

5. PracticeDone

   Install a group, then see it as a set

   List the available package groups, show which packages are in the Development Tools group, and install the mandatory and default members of that group. Afterwards remove the group again.

   Check your result

   dnf group list shows Development Tools. dnf group info 'Development Tools' lists members. After install gcc --version works; after removal rpm -q gcc says not installed (unless something else needs it).

   Hint

   Quote group names that contain a space. dnf group install "Development Tools" and dnf group remove.

   Solution

   dnf group list
   dnf group info "Development Tools"
   sudo dnf group install -y "Development Tools"
   gcc --version | head -1
   sudo dnf group remove -y "Development Tools"

6. ChallengeDone

   Undo a change

   Install tree, find that transaction in the history, show what it did, and undo it. Then identify, from the history alone, who ran the very first transaction on this machine and when.

   Check your result

   dnf history lists the install with an ID. dnf history info ID shows Packages Altered with tree. After sudo dnf history undo ID the package is removed.

   Hint

   dnf history, dnf history info N, dnf history undo N. The last entry in the list is the oldest.

   Solution

   sudo dnf install -y tree
   dnf history | head -4
   id=$(dnf history | awk 'NR>2 {print $1; exit}')
   dnf history info "$id"
   sudo dnf history undo -y "$id"
   rpm -q tree
   dnf history | tail -3