add ppid

Signed-off-by: Efertone <efertone@pm.me>

aliases.zsh

@@ -71,3 +71,7 @@ sign-iauth() { echo "${1}" | gpg --clearsign --armor }
 docker-overview() {
   docker ps --format "table {{.Names}}\t{{.State}}\t{{.Status}}\t{{.Image}}"
 }
+
+ppid() {
+  ps -p ${1:-$$} -o ppid=
+}