Can't kill processes

[Jongi]

I have found of late that the kill command in a terminal is not able to kill/terminate running processes. Is there now a stronger command? Or is there a fault somewhere?

[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# ps aux | grep opera
jongi     4024 15.9  5.2 206256 108676 ?       Rl   00:50   8:26 /usr/lib/opera/9.51/opera
root      6961  0.0  0.0   4124   712 pts/1    S+   01:43   0:00 grep opera
[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# ps aux | grep opera
jongi     4024 17.9  5.2 206256 108676 ?       Rl   00:50   9:44 /usr/lib/opera/9.51/opera
[root@Jongi-Laptop ~]# ps aux | grep opera
jongi     4024 18.1  5.2 206256 108676 ?       Rl   00:50   9:50 /usr/lib/opera/9.51/opera
[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# kill 4024
[root@Jongi-Laptop ~]# ps aux | grep opera
jongi     4024 18.2  5.2 206256 108676 ?       Rl   00:50   9:55 /usr/lib/opera/9.51/opera
root      7032  0.0  0.0   4120   676 pts/1    R+   01:44   0:00 grep opera

EDIT: To clarify, it will kill most. But there are some programs it just cannot kill. I am running KDE4(.099) and even a Ctrl-ESC doesn't help.

[PabloTwo]

There is a more potent variant of the kill command that will usually handle those stubborn processes that won't die with the regular kill command. Try:

kill -KILL <pid>

[sidebrnz]

The kill command sends a signal to the process. In general, what that process does with the signal depends on both the process and signal. There is, however, one signal that means "Die. right now. No excuses." If that's what you want, try this:

kill -9 XXXX

and process XXXX will die the death right then. Do not, under any circumstances try doing that with process #1, as that's init, and will kill all its children, which means your system will stop.

[Jongi]

That's what I needed to kill a process with no issue

kill -9 xxxx

thanks

[forkbomb]

Just to clarify:
The normal kill command without arguments really isn't all that "violent" despite what we'd guess judging by the name. Normal kills are really more like friendly requests than orders; apps can be programmed to trap normal kills and - frankly - ignore them.

That's why stuff can't always be killed. It's not a Linux malfunction - it's an app that's been programmed to trap kills.