CentOS checks whether a software package is installed

CentOS checks whether a software package is installed
1. Run rpm-qa to check whether a software package is installed. Run rpm-qa | grep "software or package name ".
2. You can use dpkg-l to view the deb package. If you are looking for a specified software package, use dpkg-l | grep "software or package name ";
3. You can use the yum list installed method to find the specified package. If you want to find the specified package, add | grep "software name or package name" after the command ";
4、if the source code package is compiled and installed, for example, in the form of .tar.gz?tar.bz2, this can only be used to check whether the executable file exists,
Neither of the above methods can see the packages installed in this source code form. If the program is installed as a root user, the executable program is usually in the/sbin:/usr/bin directory.