系统内核版本：cat /proc/version
Linux version 2.6.33-cdl (root@Phenom) (gcc version 3.4.6) #1 SMP PREEMPT Fri Apr 2 01:04:03 EDT 2010
文件系统：127 15:50$ busybox
BusyBox v1.15.3 (2010-03-05 00:33:26 EST) multi-call binary
Copyright (C) 1998-2008 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.
嵌入式文件系统一般用户执行su root切换根用户提示错误：
su: must be suid to work properly
解决方法：
修改busybox权限，chmod 4755 busybox
0 15:20$ must be suid to work properly
-bash: must: command not found
127 15:20$ chmod 4755 busybox
chmod: busybox: No such file or directory
1 15:21$ cd /
0 15:21$ chmod 4755 busybox
chmod: busybox: No such file or directory
没有那个文件或目录！
1 15:22$ sudo find -name busybox
./.cdl/initrd/bin/busybox
./bin/busybox
0 15:22$ chmod 4755 ./bin/busybox
chmod: ./bin/busybox: Operation not permitted
1 15:23$ sudo chmod 4755 ./bin/busybox
再执行su root就可以了。
但在CDLinux下不知道root用户密码，好像是没有密码，
直接执行：sudo su 就可以了。
Ubuntu的sudo与su命令使用与开启root帐户