How to install .deb files under Linux system?

deb is the format of ubuntu and debian.
rpm is the format of redhat, fedora, and suse.

They are not generic (although it can be converted a bit).

deb is the package of the debian distribution.
ubuntu is all available based on the debian distribution.

deb is the suffix of the installation package under the solaris system. The installation method is as follows:

cd to the installation package directory

dpkg -i installation package name

If you are using red hat linux, then run the following command to install

cd to the installation package directory
rpm -ivh installation package name