Linux System - Table 12 > Packages - Table 1 & 2 > patch

The patch program applies diff files to originals. The diff command isused to compare an original to a changed file. Diff lists the changesmade to the file. A person who has the original file can then use thepatch command with the diff file to add the changes to their originalfile (patching the file). Patch should be installed because it is acommon way of upgrading applications.