diff --git a/tools/fast8.sh b/tools/fast8.sh
index 22976ce09b8..24fab0395fb 100755
--- a/tools/fast8.sh
+++ b/tools/fast8.sh
@@ -11,15 +11,22 @@ fi
 echo "Checking last $NUM_COMMITS commits."
 
 cd $(dirname "$0")/..
-CHANGED=$(git diff --name-only HEAD~${NUM_COMMITS} | tr '\n' ' ')
+CHANGED=""
+CHANGED+="$(git diff --name-only HEAD~${NUM_COMMITS} \*.py | tr '\n' ' ')"
+
+while [[ -z $CHANGED ]]; do
+	# Search back until we find a commit containing python files
+    NUM_COMMITS=$((NUM_COMMITS + 1))
+    CHANGED+="$(git diff --name-only HEAD~${NUM_COMMITS} \*.py | tr '\n' ' ')" ;
+done
 
 # Skip files that don't exist
 # (have been git rm'd)
 CHECK=""
 for FILE in $CHANGED; do
     if [ -f "$FILE" ]; then
-        CHECK="$CHECK $FILE"
+        CHECK+="$FILE "
     fi
 done
 
-diff -u --from-file /dev/null $CHECK | flake8 --diff
+flake8 $CHECK