Re: [Help-bash] Capturing crash using stderr redirection

[Bob Proulx]

suvayu ali wrote:
> I am trying to run a job on an SL 5.7 node which is crashing (some
> malloc problem). So I wanted to capture the crash by redirecting
> stderr to my log file like this:
> 
> $ job_command <args> &> log &
> 
> But everything except the crash is recorded in log. Without any
> redirection, I see the crash on my terminal. Right now I have worked
> around it by using the logging feature in screen. This is with bash
> 3.2.25(1)-release. Does anyone know what could be the problem?

Normally libc buffers output when it is sent to a file but not when it
is sent to a tty.  When redirected to a file it won't be a tty and
will be buffered.  If the program crashes unexpectedly and without
flushing buffers then data might be lost in one case but not the other
case.

Here is a reference you might find useful:

  http://www.pixelbeat.org/programming/stdio_buffering/

Then you might try one of the techniques detailed there to cause the
output to be unbuffered.

Bob