The xml-coreutils are a set of command line tools for reading and writing XML files in a Unix/POSIX type shell environment. The tools try to be as close as possible to the traditional text processing tools cat, echo, sed, etc.
Xmlpatch is a simple utility to change XML files. It takes a patch file containing a list of changes and applies them to the files specified in the patch file or on the command line. Its command line interface is similar to the well known patch utility.