diff --git a/acme.sh b/acme.sh
index e39a146be2..03d4c55257 100755
--- a/acme.sh
+++ b/acme.sh
@@ -1442,7 +1442,7 @@ _toPkcs() {
   else
     ${ACME_OPENSSL_BIN:-openssl} pkcs12 -export -out "$_cpfx" -inkey "$_ckey" -in "$_ccert" -certfile "$_cca"
   fi
-  if [ "$?" == "0" ]; then
+  if [ "$?" = "0" ]; then
     _savedomainconf "Le_PFXPassword" "$pfxPassword"
   fi