diff --git a/test/lib/functions.sh b/test/lib/functions.sh
index 8cf4db6..b2e20cd 100644
--- a/test/lib/functions.sh
+++ b/test/lib/functions.sh
@@ -174,9 +174,9 @@ simulateAndCompare() {
     simulate $cvv_vcd $cvv_log $cv $tb
 
     # clean log files by removing filenames
-    sed -E 's#'$ve':[[:digit:]]+#'$ve'#g' $ref_log > $ref_log.tmp && mv $ref_log.tmp $ref_log
-    sed -E 's#'$cs':[[:digit:]]+#'$ve'#g' $cvs_log > $cvs_log.tmp && mv $cvs_log.tmp $cvs_log
-    sed -E 's#'$cv':[[:digit:]]+#'$ve'#g' $cvv_log > $cvv_log.tmp && mv $cvv_log.tmp $cvv_log
+    sed -i.bak -E 's#'$ve':[[:digit:]]+#'$ve'#g' $ref_log
+    sed -i.bak -E 's#'$cs':[[:digit:]]+#'$ve'#g' $cvs_log
+    sed -i.bak -E 's#'$cv':[[:digit:]]+#'$ve'#g' $cvv_log
 
     # compare reference verilog to converted succinct
     output=`diff $ref_vcd $cvs_vcd`