diff --git a/src/tm_mad/qcow2/clone b/src/tm_mad/qcow2/clone
index 61b80177f7..bbce31ac90 100755
--- a/src/tm_mad/qcow2/clone
+++ b/src/tm_mad/qcow2/clone
@@ -90,9 +90,7 @@ http://*)
 *)
     log "Cloning $SRC_PATH in $DST"
 
-    if [ -n $ORIGINAL_SIZE ]; then
-        ORIGINAL_SIZE="0"
-    fi
+    ORIGINAL_SIZE=${ORIGINAL_SIZE:-0}
 
     if [ "$SIZE" -ge "$ORIGINAL_SIZE" ]; then
        RESIZE_CMD="; qemu-img resize ${DST_PATH} ${SIZE}M"
diff --git a/src/tm_mad/shared/clone b/src/tm_mad/shared/clone
index 69525d0621..efb151d4d0 100755
--- a/src/tm_mad/shared/clone
+++ b/src/tm_mad/shared/clone
@@ -95,9 +95,7 @@ http://*)
 *)
     log "Cloning $SRC_PATH in $DST"
 
-    if [ -n $ORIGINAL_SIZE ]; then
-        ORIGINAL_SIZE="0"
-    fi
+    ORIGINAL_SIZE=${ORIGINAL_SIZE:-0}
 
     if [ "$SIZE" -ge "$ORIGINAL_SIZE" ]; then
        RESIZE_CMD="; qemu-img resize ${DST_PATH} ${SIZE}M"
diff --git a/src/tm_mad/ssh/clone b/src/tm_mad/ssh/clone
index 8e01fa89aa..e145fba522 100755
--- a/src/tm_mad/ssh/clone
+++ b/src/tm_mad/ssh/clone
@@ -93,9 +93,7 @@ http://*)
             "Error copying $SRC to $DST"
     fi
 
-    if [ -n $ORIGINAL_SIZE ]; then
-        ORIGINAL_SIZE="0"
-    fi
+    ORIGINAL_SIZE=${ORIGINAL_SIZE:-0}
 
     if [ "$SIZE" -ge "$ORIGINAL_SIZE" ]; then
        RESIZE_CMD="qemu-img resize ${DST_PATH} ${SIZE}M"