diff --git a/weave b/weave
index 85158fd3..9d6bb1f4 100755
--- a/weave
+++ b/weave
@@ -12,6 +12,18 @@ fi
 
 IMAGE_VERSION=${VERSION:-$IMAGE_VERSION}
 
+# These are potentially used for remote execs, and have defaults, so
+# we introduce them here
+DOCKER_BRIDGE=${DOCKER_BRIDGE:-docker0}
+PROCFS=${PROCFS:-/proc}
+
+BASE_IMAGE=$DOCKERHUB_USER/weave
+BASE_DNS_IMAGE=$DOCKERHUB_USER/weavedns
+BASE_EXEC_IMAGE=$DOCKERHUB_USER/weaveexec
+IMAGE=$BASE_IMAGE:$IMAGE_VERSION
+DNS_IMAGE=$BASE_DNS_IMAGE:$IMAGE_VERSION
+EXEC_IMAGE=$BASE_EXEC_IMAGE:$IMAGE_VERSION
+
 usage() {
     echo "Usage:"
     echo "weave setup"
@@ -37,20 +49,6 @@ usage() {
     exit 1
 }
 
-[ $# -gt 0 ] || usage
-
-# These are potentially used for remote execs, and have defaults, so
-# we introduce them here
-DOCKER_BRIDGE=${DOCKER_BRIDGE:-docker0}
-PROCFS=${PROCFS:-/proc}
-
-BASE_IMAGE=$DOCKERHUB_USER/weave
-BASE_DNS_IMAGE=$DOCKERHUB_USER/weavedns
-BASE_EXEC_IMAGE=$DOCKERHUB_USER/weaveexec
-IMAGE=$BASE_IMAGE:$IMAGE_VERSION
-DNS_IMAGE=$BASE_DNS_IMAGE:$IMAGE_VERSION
-EXEC_IMAGE=$BASE_EXEC_IMAGE:$IMAGE_VERSION
-
 exec_remote() {
     docker run --rm \
         -v /var/run/docker.sock:/var/run/docker.sock \
@@ -66,6 +64,8 @@ exec_remote() {
         $EXEC_IMAGE --local "$@"
 }
 
+[ $# -gt 0 ] || usage
+
 # "run" is a special case because we want to use docker directly,
 # rather than the docker in $EXEC_IMAGE remotely. That's because we
 # are passing arbitrary arguments on to docker run, and we can't rely