diff --git a/detach_disks.sh b/detach_disks.sh
index 67d5f7e..c514208 100644
--- a/detach_disks.sh
+++ b/detach_disks.sh
@@ -1,10 +1,10 @@
 #!/bin/sh
 
-DASDFILE=/tmp/dasd.list.${mcookie}
-DETFILE=/tmp/detach.disks.${mcookie}
-KEEPFILE=/tmp/keep.disks.${mcookie}
-NICFILE=/tmp/nic.list.${mcookie}
-FAILFILE=/tmp/error.${mcookie}
+DASDFILE=/tmp/dasd.list.$(mcookie)
+DETFILE=/tmp/detach.disks.$(mcookie)
+KEEPFILE=/tmp/keep.disks.$(mcookie)
+NICFILE=/tmp/nic.list.$(mcookie)
+FAILFILE=/tmp/error.$(mcookie)
 
 function expand_RANGE(){
 local RANGE=${1}