shell syntax optimized and more options for rebase-vm.sh

roles/lmn_vm/files/create-clone.sh

@@ -3,9 +3,8 @@
 
 set -eu
 
-# if less than one arguments supplied, display usage
-if [  "$#" -ne 1 ]
-then
+# if less or more than one arguments supplied, display usage
+if [[ $# -ne 1 ]]; then
     echo "This script takes as input the name of the VM to clone"
     echo "Usage: $0 vm_name"
     exit 1
@@ -16,7 +15,7 @@ cd /var/lib/libvirt/images
 
 VM_NAME=$1
 
-if [ ! -f "xml/${VM_NAME}.xml" -a -f "${VM_NAME}.gcow2" ]; then
+if [[ ! -f "xml/${VM_NAME}.xml" ]] || [[ ! -f "${VM_NAME}.gcow2" ]]; then
     echo "xml or qcow2 File does not exists."
     exit 1
 fi