How can one send a Ctrl-Break to a running Linux process?

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+2 Q:

How can one send a Ctrl-Break to a running Linux process?

I am debugging a memory leak in an application running on Sun's JDK 1.4.2_18. It appears that this version supports the command line param -XX:+HeapDumpOnCtrlBreak which supposedly causes the JVM to dump heap when it encounters a control-break. How does one send this to a background process on a Linux box? It appears that kill signals are the way this ought to work, but I kill -l doesn't report anything that is obviously a Ctrl-Break, at least on my Ubuntu box.

Update: I tested Kill -3 with Sun JDK 1.4.2_18 (_14 was the first to dump heap this way), and it worked. A heap dump file was created, and the process was still running.

+2 A:

Ctrl-\ is the UNIX/Linux equivalent of Windows Ctrl-Break. Wikipedia also tells me that you can also use Ctrl-4 or SysRq on the Linux virtual console (I guess you'd need something weird for a normal terminal emulator to pass representations of those key presses (over ssh/telnet)).

Tom Hawtin - tackline 2009-05-11 21:38:15

Yes, usually the terminal is bound for C-\ to send SIGQUIT. This is configurable with `stty quit`, and I'm not sure if it's the default on all systems.

ephemient 2009-05-11 22:39:45

+3 A:

kill -QUIT might do it (it will generate a thread dump which is generated by ctrl-break on windows. I haven't tried it with the heap dump option though).

bm212 2009-05-11 21:53:14

I don't have a linux box with a jvm that supports the -XX:+HeapDumpOnCtrlBreak option so can't test this (and I've never actually done it so can't vouch that it works).

bm212 2009-05-11 22:10:46

I'd much rather see a suggestion of "kill -QUIT" than "kill -3", even though they're equivalent.

ephemient 2009-05-11 22:40:52

I've edited it to say kill -QUIT.

bm212 2009-05-12 08:11:02

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How can one send a Ctrl-Break to a running Linux process?

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