Add a few more error checks

Add a few more error checks. Add feature to request help.

Signed-off-by: Scott Lowe <[email protected]>

Author: scottslowe

dmcontext

@@ -9,6 +9,11 @@ if [ "$#" -ne 1 ]; then
     exit 1
 fi
 
+if [ "$1" = "--help" ]; then
+    echo "Usage: dmcontext <name-of-machine-created-by-docker-machine>"
+    exit 0
+fi
+
 # Set the name of the machine against which the script will operate
 MACHINE=$1