Any system or network administrator should know the importance of applying patches to the various software’s running on their servers be it the numerous bug fixes or vulnerability checks.

Syntax: patch [options] [originalfile [patchfile]]

but usually just patch -pnum <patchfile

ex: patch –p1 > ../xyz.patch

Patch takes a patch file patchfile containing a difference listing produced by the diff program and applies those differences to one or more original files, producing patched versions. Normally the patched versions are put in place of the originals.

Reference:

#man patch