Re: Interesting race condition...

[Bill Davidsen]

Rob Landley wrote:
> On Friday 23 July 2004 05:01, P. Benie wrote:
>
> > On Fri, 23 Jul 2004, Rob Landley wrote:
> >
> > > I just saw a funky thing.  Here's the cut and past from the xterm...
> > >
> > > [root@(none) root]# ps ax | grep hack
> > > 9964 pts/1    R      0:00 grep hack HOSTNAME= SHELL=/bin/bash TERM=xterm
> > > HISTSIZE=1000 USER=root
> > > LS_COLORS=no=00:fi=00:di=00;34:ln=00;36:pi=40;33:so=00;35:bd=40;33;01:cd=
> > > 40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=00;32:*.cmd=00;32:*.exe=00;32:*.
> > > com=00;32:*.btm=00;32:*.bat=00;32:*.sh=00;32:*.csh=00;32:*.tar=00;31:*.tgz
> > > = [root@(none) root]# ps ax | grep hack
> > > 9966 pts/1    S      0:00 grep hack
> > >
> > > Seems like some kind of race condition, dunno if it's in Fedore Core 1's
> > > ps or the 2.6.7 kernel or what...
> >
> > The race is in the shell's pipeline - the processes don't start at exactly
> > the same time, and sometimes ps has completed before the shell has
> > started grep. This is the expected behaviour.
>
>
> It's expected behavior for PS to show a process's environment variables as 
> part of its command line?

When piped. For instance
  ps eaxf
does not, while
  ps eaxf | cat
does, at least on my systems. I tried on RHEL AS3.0 thru a four year old 
version of Slackware, all did the same thing.


--
   -bill davidsen (davidsen@xxxxxxx)
"The secret to procrastination is to put things off until the
 last possible moment - but no longer"  -me
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