+[ -n "$ARGV" -a -n "$CONF_BACKUP" ] && {
+ cat <<-EOF
+ -b/--create-backup does not perform a firmware upgrade. Do not
+ specify both -b and a firmware image.
+ EOF
+ exit 1
+}
+
+# prevent messages from clobbering the tarball when using stdout
+[ "$CONF_BACKUP" = "-" ] && export VERBOSE=0
+