关于SIGKILL SIGQUIT

SIGQUIT 3 Core Quit from keyboard

SIGKILL 9 Term Kill signal

SIGQUIT 可以用ctrl+\ 发送给当前进程，退出时产生core dump。

SIGKILL被发送给一个程序时，它使程序立即终止。与SIGTERM和SIGINT相比，这个信号不能被捕获或忽略，同时接收这个信号的进程在收到这个信号时不能执行任何清理。

9是信号量，kill实际上是用来发送信号量给进程，你可以通过man kill查看信号量列表，这里给你一个我获得的信号量列表：
Name     Num   Action    Description
0          0   n/a       exit code indicates if a signal may be sent
ALRM      14   exit
HUP        1   exit
INT        2   exit
KILL       9   exit      cannot be blocked
PIPE      13   exit
POLL           exit
PROF           exit
TERM      15   exit
USR1           exit
USR2           exit
VTALRM         exit
STKFLT         exit      might not be implemented
PWR            ignore    might exit on some systems
WINCH          ignore
CHLD           ignore
URG            ignore
TSTP           stop      might interact with the shell
TTIN           stop      might interact with the shell
TTOU           stop      might interact with the shell
STOP           stop      cannot be blocked
CONT           restart   continue if stopped, otherwise ignore
ABRT       6   core
FPE        8   core
ILL        4   core
QUIT       3   core
SEGV      11   core
TRAP       5   core
SYS            core      might not be implemented
EMT            core      might not be implemented
BUS            core      core dump might fail
XCPU           core      core dump might fail
XFSZ           core      core dump might fail

参考
http://bbs.chinaunix.net/thread-1919869-1-1.html http://zhidao.baidu.com/link?url=KA77oyYFGC0L423AiuQa7wsTrSBYSEiDYES99SfVD2oHifQBjq1eAopGJMDuR89cXMNPacoXAd5JJzv8NAQstq