List or Count Installed RPM Packages

If you are on a RPM-based Linux platform (such as Redhat, CentOS, Fedora, ArchLinux, Scientific Linux, etc.), here are two ways to determine the list of packages installed. Using yum: yum list installed Using rpm: rpm -qa You can also easily get a count of the installed packages by piping the output to wc: yum list installed | wc -l rpm -qa | wc -l