diff --git a/tests/scripts/doxygen.sh b/tests/scripts/doxygen.sh
index 2c523ba..e355073 100755
--- a/tests/scripts/doxygen.sh
+++ b/tests/scripts/doxygen.sh
@@ -35,7 +35,7 @@
     grep -v "warning: ignoring unsupported tag" \
     > doc.filtered
 
-if egrep "(warning|error):" doc.filtered; then
+if grep -E "(warning|error):" doc.filtered; then
     echo "FAIL" >&2
     exit 1;
 fi