diff --git a/tools/check_file_diff_approvals.sh b/tools/check_file_diff_approvals.sh
index 1ebe0ebb71f8d4d21e0ad6b0427c1d1efbd9beea..cce0df220c87f9ce76293904e4b37708cf0f71a7 100644
--- a/tools/check_file_diff_approvals.sh
+++ b/tools/check_file_diff_approvals.sh
@@ -278,10 +278,10 @@ if [ "${ALL_PADDLE_ENFORCE}" != "" ] && [ "${GIT_PR_ID}" != "" ]; then
     check_approval 1 6836917 47554610 22561442
 fi
 
-ALL_ADDED_LINES=`git diff -U0 upstream/$BRANCH |grep "^+" || true`
-ALL_PADDLE_CHECK=`echo $ALL_ADDED_LINES |grep -zoE "(PADDLE_ENFORCE[A-Z_]{0,9}|PADDLE_THROW)\(.[^,\);]*.[^;]*\);\s" || true`
-VALID_PADDLE_CHECK=`echo "$ALL_PADDLE_CHECK" | grep -zoE '(PADDLE_ENFORCE[A-Z_]{0,9}|PADDLE_THROW)\((.[^,;]+,)*.[^";]*(errors::).[^"]*".[^";]{20,}.[^;]*\);\s' || true`
-INVALID_PADDLE_CHECK=`echo "$ALL_PADDLE_CHECK" |grep -vxF "$VALID_PADDLE_CHECK" || true`
+ALL_ADDED_LINES=$(git diff -U0 upstream/$BRANCH |grep "^+" || true)
+ALL_PADDLE_CHECK=$(echo $ALL_ADDED_LINES |grep -zoE "(PADDLE_ENFORCE[A-Z_]{0,9}|PADDLE_THROW)\(.[^,\);]*.[^;]*\);\s" || true)
+VALID_PADDLE_CHECK=$(echo "$ALL_PADDLE_CHECK" | grep -zoE '(PADDLE_ENFORCE[A-Z_]{0,9}|PADDLE_THROW)\([^",;]*errors::.[^"]*".[^";]{20,}.[^;]*\);\s' || true)
+INVALID_PADDLE_CHECK=$(echo "$ALL_PADDLE_CHECK" |grep -vxF "$VALID_PADDLE_CHECK" || true)
 if [ "${INVALID_PADDLE_CHECK}" != "" ] && [ "${GIT_PR_ID}" != "" ]; then
     echo_line="The error message you wrote in PADDLE_ENFORCE{_**} or PADDLE_THROW does not meet our error message writing specification. Possible errors include 1. the error message is empty / 2. the error message is too short / 3. the error type is not specified. Please read the specification [ https://github.com/PaddlePaddle/Paddle/wiki/Paddle-Error-Message-Writing-Specification ], then refine the error message. If it is a mismatch, please request chenwhql (Recommend), luotao1 or lanxianghit review and approve.\nThe PADDLE_ENFORCE{_**} or PADDLE_THROW entries that do not meet the specification are as follows:\n${INVALID_PADDLE_CHECK}\n"
     check_approval 1 6836917 47554610 22561442