Better git(1) diffs

Good old POSIX diff(1) can output diffs (patch files) in serveral formats, "normal", ed(1), and the more useful ones: copied context and the newer unified context. git-diff(1) however can only output in unified context, often it's quite good (although it is not fully-reverseble if you ignore whitespace differences), however it can become quite messy at times because it mixes the old version and the new version in the same part of each hunk, where as copied context first displays the old version of the hunk and then the new version of the hunk (if there is nothing removed however the old version is skipped, and if there is nothing added, the new version is skipped). In others words, copied context is similar to side-by-side, except vertical. You can add the following script to your PATH as git-cdiff, which will let you type git cdiff instead of git diff if you want to see your changes in copied context format rather than unified context format.

#!/bin/sh
if test -z "${GIT_CDIFF_CONTEXT}"; then
	git difftool -y -x "diff -c --color=always" "$@"
elif echo "${GIT_CDIFF_CONTEXT}" | grep -q '^-'; then
	git difftool -y -x "diff ${GIT_CDIFF_CONTEXT} --color=always" "$@"
else
	git difftool -y -x "diff -C${GIT_CDIFF_CONTEXT} --color=always" "$@"
fi | {
	if test "$TERM" = linux; then
		sed '/^\(\x1b\[[0-9;]*m\)* /s/\x1b\[[0-9;]*m//g'
	else
		sed '/^\(\x1b\[[0-9;]*m\)* /s/^/\x1b\[2m/g'
	fi
} | {
	if test -t 1; then
		ifne less -R
	else
		cat
	fi
}