diff --git a/tools/install_venv.py b/tools/install_venv.py
index 96b8279..d6d9c8e 100644
--- a/tools/install_venv.py
+++ b/tools/install_venv.py
@@ -48,11 +48,11 @@
 def main(argv):
     root = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 
-    if os.environ.get('tools_path'):
-        root = os.environ['tools_path']
+    if os.environ.get('TOOLS_PATH'):
+        root = os.environ['TOOLS_PATH']
     venv = os.path.join(root, '.venv')
-    if os.environ.get('venv'):
-        venv = os.environ['venv']
+    if os.environ.get('VENV'):
+        venv = os.environ['VENV']
 
     pip_requires = os.path.join(root, 'requirements.txt')
     test_requires = os.path.join(root, 'test-requirements.txt')
diff --git a/tools/install_venv_common.py b/tools/install_venv_common.py
index 743b59d..e279159 100644
--- a/tools/install_venv_common.py
+++ b/tools/install_venv_common.py
@@ -101,6 +101,7 @@
             print('done.')
         else:
             print("venv already exists...")
+            pass
 
     def pip_install(self, *args):
         self.run_command(['tools/with_venv.sh',
@@ -124,7 +125,7 @@
         parser.add_option('-n', '--no-site-packages',
                           action='store_true',
                           help="Do not inherit packages from global Python "
-                               "install")
+                               "install.")
         return parser.parse_args(argv[1:])[0]
 
 
diff --git a/tools/with_venv.sh b/tools/with_venv.sh
index 550c477..165c883 100755
--- a/tools/with_venv.sh
+++ b/tools/with_venv.sh
@@ -1,4 +1,6 @@
 #!/bin/bash
-TOOLS=`dirname $0`
-VENV=$TOOLS/../.venv
-source $VENV/bin/activate && "$@"
+TOOLS_PATH=${TOOLS_PATH:-$(dirname $0)/../}
+VENV_PATH=${VENV_PATH:-${TOOLS_PATH}}
+VENV_DIR=${VENV_DIR:-/.venv}
+VENV=${VENV:-${VENV_PATH}/${VENV_DIR}}
+source ${VENV}/bin/activate && "$@"