Set correct terminal size to improve login over serial port experience

[Mark Shuttleworth]

For people who use ipmiconsole or other serial port access to servers a great deal it would be helpful to set LINES and COLUMNS correctly on login. There are a number of ways to do this. I found a small (10k) C application at:

http://web.archive.org/web/20081224152013/http://www.davehylands.com/gumstix-wiki/resize/resize.c

which works nicely. It appears to be a simplified version of the resize command in xterm (which has too many dependencies for comfortable server usage). It seems quite old (2006) so there may be a better, newer version of this. Perhaps it would be better named tty-resize.

I added the following two lines to .profile which then invoke the resize command on login:

# size the terminal for login over serial
[[ $(tty) == /dev/ttyS* ]] & /usr/local/bin/resize

I think remote serial usage is interesting for cloud and server farm use cases which are a big part of Ubuntu usage, so would like to improve experience in these cases across the board. This is a small part of that.

[Mark Shuttleworth (sabdfl)]

Hmm... that .profile causes this on SSH logins, so needs tweaking:

Last login: Sat Jan 5 10:49:02 2019 from 192.168.4.70
[1]+ Exit 1 [[ $(tty) == /dev/ttyS* ]]
john@xx:~$

[Mark Shuttleworth (sabdfl)]

&& works better :)