modify basic filestructure

It's unclear what's 'basic', so `basic/` notes have been mostly moved.
The remainder became `shell/`.

shell/locate_program.md

@@ -0,0 +1,28 @@
+---
+title: "locating"
+tags: [ "basics" ]
+---
+# Type
+
+`type` shows what kind of thing you're running, be it an alias, function, or binary program.
+
+```sh
+type cd
+type ls
+type -P ls
+type -a cat
+```
+
+# Whereis the Program
+
+Where is `grep` and all its configuration files?
+
+```sh
+whereis grep
+```
+
+Which one of these is the binary file which you actually use?
+
+```sh
+which grep
+```