In order to administer the installation or to update the software in our system, we will, in the first instance, depend on the type of software packages used by our system:
RPM: packages that use the Fedora/Red Hat distribution (and derivatives). They are usually handled through the rpm command. Contains information on the dependencies that the software has on other software. At a high level, through Yum (or up2date in some distributions derived from Red Hat).
DEB: Debian packages that are usually handled with a set of tools that work on different levels with individual packages or groups. Among these, we must mention: dselect, tasksel, dpkg, and apt-get.
Tar or the tgz (also tar.gz): these are simply package files that have been joined and compressed using standard commands such as tar, and gzip (these are used for decompressing). The packages do not contain information on any dependencies and can normally be installed in different places if they do not carry any absolute root (path) information.
There are various graphical tools for handling these packages, such as RPM: Kpackage; DEB: Synaptic, Gnome-apt; Tgz: Kpackage,or from the actual graphic file manager itself (in Gnome or KDE). There are also usually package conversion utilities. For example, in Debian we have the alien command, with which we can change RPM packages to DEB packages. Although it is necessary to take the appropriate precautions, so that the package does not unexpectedly modify any behaviour or file system, as it has a different destination distribution.
Depending on the use of the types of packages or tools: it will be possible to update or install the software in our system in different ways:
1) From the actual system installation CDs; normally, all the distributions search for the software on the CDs. But the software should be checked to ensure that it is not old and does not, therefore, include some patches like updates or new versions with more features; consequently, if a CD is used for installation, it is standard practice to check that it is the latest version and that no more recent version exists.
2) Through updating or software search services, whether they are free, as is the case with Debian's apt-get tool or yum in Fedora, or through subscription services (paid services or services with basic facilities), such as the Red Hat Network of the commercial Red Hat versions.
3) Through software repositories that offer pre-built software packages for a determined distribution.
4) From the actual creator or distributor of the software, who may offer a series of software installation packages. We may find that we are unable to locate the type of packages that we need for our distribution.
5) Unpackaged software or with compression only, without any type of dependencies.
6) Only source code, in the form of a package or compressed file.