Patch Howto
1)
Diff
diff is a shell command that compares the content of files and reports differences. The term diff is also used to identify the output of the command and is used as a verb for running the command. To diff files, one runs diff to create a diff.
-ruP original modified > patch
2)
Patch (Unix)
patch is a shell command that updates text files according to instructions in a separate file, called a patch file. The patch file is a text file that lists the differences between the input file and the desired content. The command is designed to support patch files created via diff. A user creates a patch file by running diff for two versions of a file (original and target) which produces a list of differences that patch can later use to generate the target file from the original file plus the patch file. The term patch is also a verb – meaning to apply a patch.
-p0 < patch