적외선 2012. 4. 26. 10:33

프로세스가 존재할 경우에 0을 리턴하고, 그렇지 않을 경우에 1을 리턴한다.


Example

chris@chris-laptop:~$ sleep 60 &
[1] 1316
chris@chris-laptop:~$ kill -0 1316 # process id of the sleep command
chris@chris-laptop:~$ echo $?
0
chris@chris-laptop:~$ kill -0 65535 # process does not exist
bash: kill: (65535) - No such process
chris@chris-laptop:~$ echo $?
1
chris@chris-laptop:~$ sudo kill -0 27835 # a kernel process
chris@chris-laptop:~$ echo $?
0