BusyBox 'find' cannot combine '-exec ... {} +' with parenthesis arguments. This should work; it is perfectly valid to use it in more complex 'find' epxressions. A simple test case: $ find /dev/null \( -exec printf '%s\n' {} + \) $ find /dev/null \( -exec printf '%s\n' {} \; \) /dev/null The first command prints nothing with Busybox 'find'; it should print '/dev/null' like the second.