Add List Parent pid With ps as a unix til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_475 TILs and counting..._
+_476 TILs and counting..._
 
 ---
 
@@ -431,6 +431,7 @@ _475 TILs and counting..._
 - [List All Users](unix/list-all-users.md)
 - [List Names Of Files With Matches](unix/list-names-of-files-with-matches.md)
 - [List Of Sessions To A Machine](unix/list-of-sessions-to-a-machine.md)
+- [List Parent pid With ps](unix/list-parent-pid-with-ps.md)
 - [Only Show The Matches](unix/only-show-the-matches.md)
 - [Open The Current Command In An Editor](unix/open-the-current-command-in-an-editor.md)
 - [Partial String Matching In Bash Scripts](unix/partial-string-matching-in-bash-scripts.md)

unix/list-parent-pid-with-ps.md

@@ -0,0 +1,13 @@
+# List Parent pid With ps
+
+The `ps` command, which stands for `process status`, is a great way to find
+different processes running on a machine. Information like their `pid`
+(_process id_) is included. If you are tracking down a process to kill and
+find that that process is an unkillable zombie, then you may need to
+simultaneously kill the process' parent as well.
+
+So, you'll need the parent `pid` as well. You can get both the `pid` and the
+parent `pid` of a process by including the `-f` flag with `ps`.
+
+You may also want to include the `-e` flag to make sure that information
+about other users' processes is included in the results.