Q：现在遇到这样一个问题，telnet一台SUN机时报下面的错误： 
No utmpx entry. You must exec "login" from the lowest level "shell". 
我做了下面的处理后： 
cd /var/adm 
mv utmpx utmpxbak 
touch utmpx 
telnet 恢复了正常，可在该机器的终端下执行login 命令时，又报了上面相同的错误。而且重新启动机器以后，telnet时还是报相同的错误！ 
A：进入单用户模式，清空(不是删除)这两个文件 
# cat /dev/null > /var/adm/wtmpx 
# cat /dev/null > /var/adm/utmpx 
之后，重新启动系统 
找了很多国外的论坛，都是这么说的： 
The problem comes if utmp or wtmp file becomes corrupted . You need to initialize these and reboot the system to correct the error. 
These files are log files and can be initialized without affecting the system, as long as you reboot the system after truncating the files. Perform these steps: 
1. Bring the system into System Maintenance mode. 
2. Make copies of the files /etc/utmp, /etc/utmpx, /etc/wtmp, and 
/etc/wtmpx before proceeding with the next step. 
3. Delete the contents of these files by executing the following 
commands: 
# > /etc/utmp 
# > /etc/wtmp 
# > /etc/utmpx 
# > /etc/wtmpx 
4. Shutdown the system: 
# shutdown -y -g0 
Restart the system