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Author Question on running a process at 100% CPU time.
K-mart Cashier

2008-01-20, 7:16 pm

A bulletin board system that I frequently visit runs OpenBSD 4.1 .
Over the course of three months, I've watched some guy from brazil run
unix 'talk', dd, the bbs editor, and the chat program at 100% cpu
time. I looked in his home directory and there is no script. I don't
have the authorization to look at his .bash_history file. I'm
suspecting he is probably using some kind of one liner. The only thing
that they all have in common is they run in the background.

I set bash to stty tostop

And tried variations on
$ talk newbie &
[1] 3994

But every time, I get the following
$
[1] + Stopped (tty output) talk newbie


What one line bash combo would generate this kind of behavior?




Bin Chen

2008-01-20, 7:16 pm

On 1=D4=C221=C8=D5, =C9=CF=CE=E77=CA=B150=B7=D6, K-mart Cashier <cdal...@gma=
il.com> wrote:
> A bulletin board system that I frequently visit runs OpenBSD 4.1 .
> Over the course of three months, I've watched some guy from brazil run
> unix 'talk', dd, the bbs editor, and the chat program at 100% cpu
> time. I looked in his home directory and there is no script. I don't
> have the authorization to look at his .bash_history file. I'm
> suspecting he is probably using some kind of one liner. The only thing
> that they all have in common is they run in the background.
>
> I set bash to stty tostop
>
> And tried variations on
> $ talk newbie &
> [1] 3994
>
> But every time, I get the following
> $
> [1] + Stopped (tty output) talk newbie
>
> What one line bash combo would generate this kind of behavior?


You can't start a process in backround which will read stdin.

Bin
Bill Marcum

2008-01-21, 4:33 am

["Followup-To:" header set to comp.unix.questions.]
On 2008-01-20, K-mart Cashier <cdalten@gmail.com> wrote:
>
>
> A bulletin board system that I frequently visit runs OpenBSD 4.1 .
> Over the course of three months, I've watched some guy from brazil run
> unix 'talk', dd, the bbs editor, and the chat program at 100% cpu
> time. I looked in his home directory and there is no script. I don't
> have the authorization to look at his .bash_history file. I'm
> suspecting he is probably using some kind of one liner. The only thing
> that they all have in common is they run in the background.
>
> I set bash to stty tostop
>
> And tried variations on
> $ talk newbie &
> [1] 3994
>
> But every time, I get the following
> $
> [1] + Stopped (tty output) talk newbie
>

That's what 'stty tostop' told it to do. Try 'stty -tostop'.

> What one line bash combo would generate this kind of behavior?
>
>
>
>

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