"The diff and patch utilites can be intimidating to the newcomer, but they are not all that difficult to use, even for the non-programmer. If you are at all familiar with makefiles, you might find yourself frequently wanting to patch a file, either to correct an error that you've found or to add something that you need to the makefile.
"After I began using the mrxvt terminal, I wanted to give it Japanese capability. My main O/S is FreeBSD..."