OpenBSD ports diff function

portsdiff.zsh

# Usage: portsdiff <diff-name>
# Creates a new diff from the current port cvs directory in DIR.
# If no parameter is passed PKGNAME will use as filename.
portsdiff () {
	local DIR="$HOME/patches"
	local SAVEFILE

	if [ ! -d "$DIR" ]; then
		echo "create $DIR"
		mkdir -p $DIR
	fi

	if [ -n "$1" ]; then
		SAVEFILE="$DIR/$1.diff"
		if [ -e "$SAVEFILE" ]; then
			echo "$SAVEFILE exist!"
			echo -n "Override $SAVEFILE? (y):"
			read yes

			if [ "$yes" == "n" ]; then
				return 0
			fi
		fi
	else
		local SAVEDIFF="$(make show=PKGNAME)"
		local DATE=$(date +%d_%m_%Y_%k%M%S)

		if [ -e "$DIR/$SAVEDIFF.diff" ]; then
			SAVEFILE="$DIR/${SAVEDIFF}_$DATE.diff"
		else
			SAVEFILE="$DIR/$SAVEDIFF.diff"
		fi
	fi

	if [ -n "$SAVEFILE" ]; then
		echo "Save diff in $SAVEFILE"
		cvs diff -uNp . 2>&1 > $SAVEFILE
	fi
}