add how bash process commands

03-how-bash-process-commands/01.sh

@@ -3,5 +3,12 @@
 # Author: Samir M.
 # Date: 2024-03-04
 # Modified: 2024-03-04
-# Description: Brace expansion
-# Usage: ./01.sh
+# Description: How bash processes command lines
+# Usage: ./01.sh
+
+
+# Bash goes through 5 steps to interpret a command line.
+
+# Step 1: Tokenisation:
+# The command line is broken into tokens. Tokens are the smallest units of a command line.
+# Tokens are separated by metacharacters, such as spaces, tabs, and newlines, | ; & ( ) < >.