Git script to scan diff --numstat output and sum it.

git-instat

#!/bin/bash

usage() {
	cat >&2 <<-'EOF'
	Usage: git-instat [range] [path...] [-path pattern...] [-only pattern...] [-omit pattern...]

	Print a stat summary for the given paths in a ref.
	If no range is given, the default is 'HEAD^1..HEAD'.

	-only and -omit may be passed to filter lines of the numstat, such that
	only lines containing none of the omitted patterns and all of the 'only'
	patterns are the only remaining outputs.

	-path arguments are any path pattern accepted by git-diff(1).
EOF
	exit 2
}

var=paths
paths=()
only=()
omit=()

ref='HEAD^1..HEAD'
case "${1---}" in
-h|--help) usage;;
-path|-omit|-only) :;;
--) shift;;
*) ref="$1"; shift;;
esac

set -e

push() {
	local var="$1"
	shift
	for arg; do
		eval "${var}"'[${#'"${var}"'[@]}]="$arg"'
	done
}

noswitch=
for arg; do
	shift
	case "${noswitch}${arg}" in
	-only) var=only; noswitch=x;;
	-omit) var=omit; noswitch=x;;
	-path) var=paths; noswitch=x;;
	*)
		push "$var" "$arg"
		noswitch=
		;;
	esac
done

if [ ${#paths[@]} -gt 0 ]; then
	paths=(-- "${paths[@]}")
fi

recurse() {
	cmd=()
	for arg; do
		shift
		if [ "$arg" = -- ]; then
			break
		fi
		push cmd "$arg"
	done

	if [ $# -eq 0 ]; then
		cat
	else
		local arg="$1"
		shift
		"${cmd[@]}" "$arg" | recurse "${cmd[@]}" -- "$@"
	fi
}

git diff --numstat "$ref" "${paths[@]}" |
	recurse grep --line-buffered -ve -- "${omit[@]}" |
	recurse grep --line-buffered -e	-- "${only[@]}" |
	awk -F $'\t' '
		BEGIN { added = deleted = 0 }
		{ added += $1; deleted += $2; print $0 }
		END { printf "%d\t%d\n", added, deleted }
	'