Create a Patch for a Single File in Linux
diff -u OriginalFile UpdatedFile > PatchFile
diff -ruN OriginalDir UpdatedDir > PatchFile
Apply a Patch to a File
patch OriginalFile < PatchFile
patch -p0 < PatchFile
Undo a Patch
patch -R OriginalFile < PatchFile
patch -R -p0 OriginalFile < PatchFile