Updated SC2069 (markdown)

SC2069.md

@@ -1 +1,21 @@
-The order of the 2>&1 and the redirect matters. The 2>&1 has to be last.
+## The order of the 2>&1 and the redirect matters. The 2>&1 has to be last.
+
+### Problematic code:
+
+    firefox 2>&1 > /dev/null
+
+### Correct code:
+
+    firefox > /dev/null 2>&1
+
+### Rationale:
+
+Redirections are handled in order. 
+
+The problematic code means "Point stderr to where stdout is currently pointing (the terminal). Then point stdout to /dev/null".
+
+The correct code means "Point stdout to /dev/null. Then point stderr to where stdout is currently pointing (/dev/null).".
+
+### Contraindications
+
+If you want stderr as stdout and stdout to a file, you can ignore this message.