diff --git a/substrate/.maintain/gitlab/check_line_width.sh b/substrate/.maintain/gitlab/check_line_width.sh
index f382d630b1..85092260b6 100755
--- a/substrate/.maintain/gitlab/check_line_width.sh
+++ b/substrate/.maintain/gitlab/check_line_width.sh
@@ -2,47 +2,49 @@
 #
 # check if line width of rust source files is not beyond x characters
 #
+set -e
+set -o pipefail
 
+BASE_ORIGIN="origin"
+BASE_BRANCH_NAME="master"
+LINE_WIDTH="120"
+GOOD_LINE_WIDTH="100"
+BASE_BRANCH="${BASE_ORIGIN}/${BASE_BRANCH_NAME}"
 
-BASE_BRANCH="origin/master"
-LINE_WIDTH="121"
-GOOD_LINE_WIDTH="101"
-
-
-git diff --name-only ${BASE_BRANCH}...${CI_COMMIT_SHA} \*.rs | ( while read file
+git fetch ${BASE_ORIGIN} ${BASE_BRANCH_NAME} --depth 1
+git diff --name-only ${BASE_BRANCH} -- \*.rs | ( while read file
 do
   if [ ! -f ${file} ];
   then
 	echo "Skipping removed file."
-  elif git diff ${BASE_BRANCH}...${CI_COMMIT_SHA} ${file} | grep -q "^+.\{${LINE_WIDTH}\}"
+  elif git diff ${BASE_BRANCH} -- ${file} | grep -q "^+.\{$(( $LINE_WIDTH + 1 ))\}"
   then
     if [ -z "${FAIL}" ]
     then
-      echo "| warning!"
-      echo "| Lines should not be longer than 120 characters."
+      echo "| error!"
+      echo "| Lines must not be longer than ${LINE_WIDTH} characters."
       echo "| "
       echo "| see more https://wiki.parity.io/Substrate-Style-Guide"
       echo "|"
       FAIL="true"
     fi
     echo "| file: ${file}"
-    git diff ${BASE_BRANCH}...${CI_COMMIT_SHA} ${file} \
-      | grep -n "^+.\{${LINE_WIDTH}\}"
+    git diff ${BASE_BRANCH} -- ${file} \
+      | grep -n "^+.\{$(( $LINE_WIDTH + 1))\}"
     echo "|"
   else
-    if git diff ${BASE_BRANCH}...${CI_COMMIT_SHA} ${file} | grep -q "^+.\{${GOOD_LINE_WIDTH}\}"
+    if git diff ${BASE_BRANCH} -- ${file} | grep -q "^+.\{$(( $GOOD_LINE_WIDTH + 1 ))\}"
     then
       if [ -z "${FAIL}" ]
       then
         echo "| warning!"
-        echo "| Lines should be longer than 100 characters only in exceptional circumstances!"
+        echo "| Lines should be longer than ${GOOD_LINE_WIDTH} characters only in exceptional circumstances!"
         echo "| "
         echo "| see more https://wiki.parity.io/Substrate-Style-Guide"
         echo "|"
       fi
       echo "| file: ${file}"
-      git diff ${BASE_BRANCH}...${CI_COMMIT_SHA} ${file} \
-        | grep -n "^+.\{${LINE_WIDTH}\}"
+      git diff ${BASE_BRANCH} -- ${file} | grep -n "^+.\{$(( $GOOD_LINE_WIDTH + 1 ))\}"
       echo "|"
     fi
   fi