diff --git a/.gitignore b/.gitignore
index 31ae422..404a8f5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,4 +33,4 @@ nosetests.xml
 .pydevproject
 
 # ignore virtualenv created by ./tools/provision
-.zulip-api-env
+zulip-api-py2-venv
diff --git a/tools/provision b/tools/provision
index 27cdbe3..9f42be3 100755
--- a/tools/provision
+++ b/tools/provision
@@ -2,15 +2,23 @@
 
 BASEDIR=`dirname $0`/..
 
-if [ ! -d "$BASEDIR/.zulip-api-env" ]; then
-    virtualenv $BASEDIR/.zulip-api-env
+if [ ! -d "$BASEDIR/zulip-api-py2-venv" ]; then
+    virtualenv $BASEDIR/zulip-api-py2-venv
     echo "Virtualenv created."
 fi
 
-source $BASEDIR/.zulip-api-env/bin/activate
+source $BASEDIR/zulip-api-py2-venv/bin/activate
+RVAL=$?
+if [ $RVAL -ne 0 ]; then
+    echo "Failed to activate virtualenv."
+    exit
+fi
 
-if [ ! -f "$BASEDIR/.zulip-api-env/updated" -o $BASEDIR/requirements.txt -nt $BASEDIR/.zulip-api-env/updated ]; then
+# Install python dependencies if needed.
+cmp $BASEDIR/zulip-api-py2-venv/installed-requirements.txt requirements.txt 2>/dev/null
+RVAL=$? # Return value of the comparision. 0 means files are same.
+if [ $RVAL -ne 0 ]; then
     pip install -r $BASEDIR/requirements.txt
-    touch $BASEDIR/.zulip-api-env/updated
+    cp requirements.txt $BASEDIR/zulip-api-py2-venv/installed-requirements.txt
     echo "Requirements installed."
 fi