diff --git a/tests/touch-obj-on-success b/tests/touch-obj-on-success
index df08a49..d8a71ba 100755
--- a/tests/touch-obj-on-success
+++ b/tests/touch-obj-on-success
@@ -4,5 +4,8 @@
 # from that command line and touches it.
 
 "$@"
-obj="$(echo "$@" | grep -oP '\S+\.o\b')"
-touch "${obj}"
+for arg in "$@"; do
+  if [[ "$arg" == *.o ]]; then
+    touch "$arg"
+  fi
+done