Patches are added using either patchadd (the recommended way) or the installpatch script that is supplied with each patch. As installpatch will soon be unsupported, we will deal exclusively with patchadd here.
Parts of the patch installation are carried out using the nobody user and this needs to be able to create directories as required. To allow this to happen, Sun recommends that patch installs should always be carried out from /tmp and the user nobody should always have an entry in the password file.
Patches can be installed with the “backout” option. This allows them to be removed should the system administrator wish, should a patch make a particular problem worse, for example, or not work with another one installed.