freebsd 9-stable TOP problem from around Jan 10

Jeremy Chadwick freebsd at
Wed Feb 15 00:20:38 UTC 2012

On Tue, Feb 14, 2012 at 03:35:01PM -0800, Julian Elischer wrote:
> On 2/14/12 10:38 AM, Kevin Oberman wrote:
> >On Tue, Feb 14, 2012 at 12:23 AM, Julian Elischer<julian at>  wrote:
> >>Has anyone else seen a  problem with top -H -S?
> >>
> >>after a short while the screen gets more and more corrupted..
> >>
> >>hitting ^L or turning off S&  H modes helps .. for a while.
> >>
> >>If this is a known fixed problem, let me know but I need to co-ordinate with
> >>others
> >>to upgrade the machine in question.
> >Not seeing it here on 9-stable. Could it be a display issue? I am
> >using gnome-terminal with TERM defined as 'xterm'.
> yeah I'm on a mac with iterm, but running through 'screen' .
> it's never been a problem before.. just since we upgraded to 9-stable.

If you remove GNU screen from the picture does the problem go away?  If
so, I'm not surprised.  :-)

Make sure that when you're using GNU screen, that all shells launched
"under/within" screen have TERM=screen.  If they don't, then this is
almost certainly the problem -- GNU screen "translates" between terminal
types, meaning it translates its own terminal type ("screen") into
whatever TERM is currently attached ("xterm", "iterm", whatever).  See
the last 4 paragraphs of my post here to understand what exactly GNU
screen is doing:

So, in general, make sure your dotfiles and so on don't mess about with
the $TERM environment variable and you should generally be okay.

If within GNU screen TERM=screen and you see the problem, but outside of
screen you use TERM=xterm (or something else) but don't see the problem,
then I would almost certainly blame GNU screen.  If you're looking for
something that simply keeps a terminal running in the background, try
nohup or tmux.

Alternately, possibly someone added a "screen" entry to /etc/termcap on
RELENG_9?  I don't use 9 so I have no way to confirm this, but on 8
there is no such entry.

| Jeremy Chadwick                              jdc at |
| Parodius Networking            |
| UNIX Systems Administrator                 Mountain View, CA, US |
| Making life hard for others since 1977.             PGP 4BD6C0CB |

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