Make a more descriptive readme

README.md

@@ -1,3 +1,13 @@
-# shellfish
+# Shellfish
 
-Examples demonstrating how command-line shells implement features.
+## About
+
+Self-contained examples demonstrating how shells implement common features.
+Every example can be built and run, however they are not meant to show how to
+write production-ready software. They only show how the important functions
+work, and not how to do things like handle and recover from errors.
+
+## Recommended Order
+
+  1. [exec.c](exec.c)
+  2. [redirection.c](redirection.c)