diff --git a/debbuild/22.04/DEBIAN/postinst b/debbuild/22.04/DEBIAN/postinst
index 2ee3ca3..7273d8c 100644
--- a/debbuild/22.04/DEBIAN/postinst
+++ b/debbuild/22.04/DEBIAN/postinst
@@ -84,7 +84,7 @@ systemctl enable captrace.service
 systemctl daemon-reload
 
 # read environment parameter and to do 
-if [ "$M_PARAM" == "install" -o "$M_PARAM" == "upgrade" ]; then
+if [ "$M_PARAM" = "install" -o "$M_PARAM" = "upgrade" ]; then
     echo "M parameter: $M_PARAM"
     if [ -n "$C_PARAM" ]; then
         echo "C parameter: $C_PARAM"
diff --git a/debbuild/DEBIAN/postinst b/debbuild/DEBIAN/postinst
index 07f2a99..1948d87 100644
--- a/debbuild/DEBIAN/postinst
+++ b/debbuild/DEBIAN/postinst
@@ -84,7 +84,7 @@ systemctl enable captrace.service
 systemctl daemon-reload
 
 # read environment parameter and to do 
-if [ "$M_PARAM" == "install" -o "$M_PARAM" == "upgrade" ]; then
+if [ "$M_PARAM" = "install" -o "$M_PARAM" = "upgrade" ]; then
     echo "M parameter: $M_PARAM"
     if [ -n "$C_PARAM" ]; then
         echo "C parameter: $C_PARAM"