Typo and warning added to help message.

Author: nzlosh

build_image

@@ -4,7 +4,7 @@ set -e +x -o pipefail
 
 function bootstrap_docker()
 {
-    usdo apt-get update --quiet --quiet
+    sudo apt-get update --quiet --quiet
     sudo apt-get install apt-transport-https ca-certificates curl gnupg-agent software-properties-common jq
 
     export CODENAME=$(source /etc/os-release && echo "$VERSION_CODENAME")
@@ -48,7 +48,7 @@ function usage()
 Usage $0 <bootstrap|build [distro]>
 
         bootstrap       - Configure the system with the Docker repository and
-                          install Docker CE and Docker Compose packages.
+                          install Docker CE and Docker Compose packages.  (Ubuntu only)
         build [distro]  - Build the Docker images for the given distro codename.
                           Builds all distros when no codename provided.