diff --git a/docs/migration-renumbering.md b/docs/migration-renumbering.md
index 4f37637ffb..1f81387563 100644
--- a/docs/migration-renumbering.md
+++ b/docs/migration-renumbering.md
@@ -85,9 +85,9 @@ semantic conflicts with the new changes from master:
 <output skipped>
 
   File "/srv/zulip-venv-cache/ad3a375e95a56d911510d7edba7e17280d227bc7/zulip-venv/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 105, in handle
-    "'python manage.py makemigrations --merge'" % name_str
+    "'./manage.py makemigrations --merge'" % name_str
 django.core.management.base.CommandError: Conflicting migrations detected (0026_topics_backfill, 0025_realm_message_content_edit_limit in zerver).
-To fix them run 'python manage.py makemigrations --merge'
+To fix them run './manage.py makemigrations --merge'
 
 <output skipped>
 
diff --git a/puppet/zulip/files/cron.d/update-analytics-counts b/puppet/zulip/files/cron.d/update-analytics-counts
index 68404c7a07..b5b9b4e4b7 100644
--- a/puppet/zulip/files/cron.d/update-analytics-counts
+++ b/puppet/zulip/files/cron.d/update-analytics-counts
@@ -3,5 +3,5 @@ PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
 USER=zulip
 
 # Run update analytics tables every 5 minutes past the hour
-5 * * * * zulip python /home/zulip/deployments/current/manage.py update_analytics_counts
+5 * * * * zulip /home/zulip/deployments/current/manage.py update_analytics_counts
 
diff --git a/tools/js-dep-visualizer.py b/tools/js-dep-visualizer.py
old mode 100644
new mode 100755
index eacb909c2d..232c32a4f0
--- a/tools/js-dep-visualizer.py
+++ b/tools/js-dep-visualizer.py
@@ -1,5 +1,6 @@
+#!/usr/bin/env python
 """
-$ python ./tools/js-dep-visualizer.py
+$ ./tools/js-dep-visualizer.py
 $ dot -Tpng var/zulip-deps.dot -o var/zulip-deps.png
 """
 
diff --git a/tools/provision b/tools/provision
index babfa5bfbb..e5fdb16538 100755
--- a/tools/provision
+++ b/tools/provision
@@ -10,26 +10,28 @@ if [ "$EUID" -eq 0 ]; then
     exit 1
 fi
 
-if [ -n "$TRAVIS" ]; then
-    PYTHON=python
-else
-    PYTHON=python3
-fi
-
 #Make the script independent of the location from where it is
 #executed
 PARENT_PATH=$( cd "$(dirname "${BASH_SOURCE}")" ; pwd -P )
 cd "$PARENT_PATH"
 mkdir -p ../var/log
 LOG_PATH="../var/log/provision.log"
-PROVISION_PATH="lib/provision.py"
 
 echo "PROVISIONING STARTING." >> $LOG_PATH
 
+PROVISION_PATH="./lib/provision.py"
+if [ -n "$TRAVIS" ]; then
+    # In CI, we let PATH provide the Python version.
+    PROVISION_CMD=("$PROVISION_PATH")
+else
+    # In dev, we force Python 3.
+    PROVISION_CMD=(python3 "$PROVISION_PATH")
+fi
+
 # PYTHONUNBUFFERED is important to ensure that tracebacks don't get
 # lost far above where they should be in the output.
 export PYTHONUNBUFFERED=1
-"$PYTHON" "$PROVISION_PATH" "$@" 2>&1 | tee -a "$LOG_PATH"
+"${PROVISION_CMD[@]}" "$@" 2>&1 | tee -a "$LOG_PATH"
 failed=${PIPESTATUS[0]}
 
 if [ $failed = 1 ]; then
diff --git a/tools/test-all b/tools/test-all
index 7a0bff7ed0..f238449704 100755
--- a/tools/test-all
+++ b/tools/test-all
@@ -41,9 +41,9 @@ run ./tools/run-mypy
 
 # travis/backend
 run ./tools/lint --pep8 $FORCEARG
-run python manage.py makemessages --locale en
-run python -W ignore tools/check-capitalization --no-generate
-run python -W ignore tools/check-frontend-i18n --no-generate
+run ./manage.py makemessages --locale en
+run PYTHONWARNINGS=ignore ./tools/check-capitalization --no-generate
+run PYTHONWARNINGS=ignore ./tools/check-frontend-i18n --no-generate
 run ./tools/test-tools
 run ./tools/test-backend $FORCEARG
 run ./tools/test-migrations
diff --git a/tools/travis/backend b/tools/travis/backend
index 67ee5a4563..18685b81b8 100755
--- a/tools/travis/backend
+++ b/tools/travis/backend
@@ -6,9 +6,9 @@ set -e
 set -x
 
 ./tools/lint --pep8 # Include the slow and thus non-default pep8 linter check
-python manage.py makemessages --locale en
-python -W ignore tools/check-capitalization --no-generate
-python -W ignore tools/check-frontend-i18n --no-generate
+./manage.py makemessages --locale en
+PYTHONWARNINGS=ignore ./tools/check-capitalization --no-generate
+PYTHONWARNINGS=ignore ./tools/check-frontend-i18n --no-generate
 
 ./tools/test-tools
 ./tools/test-backend --coverage