add debugging examples for bash

add new command route

cheat/cheatsheets/bash

@@ -12,3 +12,9 @@ in
     2) echo "two found";;
     3*) echo "something beginning with 3 found";;
 esac
+
+# Turn on debugging:
+set -x
+
+# Turn off debugging:
+set +x

cheat/cheatsheets/route

@@ -0,0 +1,5 @@
+# Add a default gateway:
+route add default gateway 192.168.0.1
+
+# Display routing table IP addresses instead of host names:
+route -n