diff --git a/tools/install_venv.py b/tools/install_venv.py
old mode 100644
new mode 100755
index ff644d5346..b05a3f8748
--- a/tools/install_venv.py
+++ b/tools/install_venv.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
@@ -102,10 +103,10 @@ def install_dependencies(venv=VENV):
     print 'Installing dependencies with pip (this can take a while)...'
     # Install greenlet by hand - just listing it in the requires file does not
     # get it in stalled in the right order
-    run_command(['tools/with_venv.sh', 'pip', 'install', '-E', venv,
+    run_command(['tools/with_venv.sh', '-E', venv, 'pip', 'install',
                  'greenlet'], redirect_output=False)
     for requires in (PIP_REQUIRES, TEST_REQUIRES):
-        run_command(['tools/with_venv.sh', 'pip', 'install', '-E', venv, '-r',
+        run_command(['tools/with_venv.sh', '-E', venv, 'pip', 'install', '-r',
                      requires], redirect_output=False)
 
     # Tell the virtual env how to "import reddwarf"
diff --git a/tools/with_venv.sh b/tools/with_venv.sh
index c8d2940fc7..633806f45d 100755
--- a/tools/with_venv.sh
+++ b/tools/with_venv.sh
@@ -1,4 +1,30 @@
 #!/bin/bash
-TOOLS=`dirname $0`
-VENV=$TOOLS/../.venv
-source $VENV/bin/activate && $@
+
+set -e
+
+me=${0##*/}
+dir="$(dirname $0)"
+
+function print_usage() {
+  cat >&2 <<EOS
+Run commands in a default (or specific) virtualenv
+
+Usage: $me [-E venv] commands
+
+Options:
+  -h        prints out this message
+  -E venv   use this virtualenv (default: ${venv})
+EOS
+}
+
+venv="${dir}/../.venv"
+
+while getopts ":hE:" opt; do
+  case "$opt" in
+    h|\?) print_usage; exit 1 ;;
+    E) venv=$OPTARG ;;
+  esac
+done
+shift $((OPTIND-1))
+
+source "${venv}/bin/activate" && $@