dtterm and LINES setting

[Dave Burton_5]

When I start a dtterm using the geometry option against the local machine, LINES is set correctly, i.e. if I run:

dtterm -display $DISPLAY -geometry 96x12+98+98

LINES is set to 12 in the new dtterm.

If I run the same command under remsh, then the LINES setting sometimes gets messed up, e.g. if I run

remsh remotehost dtterm -display $DISPLAY -geometry 96x12+98+98

LINES might come out at 13.

Why is that?

[Bill Hassell · Accepted solution]

remsh is a very different network protocol. It is not telnet without a password. Indeed, remsh is really awful with interactive processes. When you start dtterm with a specific geometry, it sets the terminal's emulation size. Then a telnet connection will negotiate about window size (NAWS in telnet terminolgy, see http://www.faqs.org/rfcs/rfc1073.html).

Changing the dtterm window size generates a SIGWINCH sondition (Window Size change) and the remote telnet destination will be notified of the new values and set LINES and COLUMNS automatically.

remsh does not do any of this type of protocol, thus the problem. You can avoid this problem by running resize or ttytype. Either program will query the terminal (dtterm) as to the current settings and generate the shell commands to change the settings. Use either one like this:

eval $(resize)
or
eval $(ttytype -a)

To see what they actually do, just type resize or ttytype -a. For a remsh connection, you'll have to do this every time you change the window size.