107. Fun with gnu screen -- setting up a screenrc

This is going to be a short post.

The problem:
If I have three nodes on a cluster, each with htop installed, how do I set up gnu screen so that it automatically signs in to each node and starts a copy of htop on each node, and display the output in a split window? Basically, how to you open screen instances and inject commands in them?

...like so. Guess which computer is running a full gnome-shell environment...

The solution:
create a file called multitop.screenrc:

screen ssh 192.168.1.101
stuff htop\015
title node01
split
focus
screen ssh 192.168.1.102
title node02
stuff htop\015
split
focus
screen ssh 192.168.1.103
title node03
stuff htop\015

stuff string injects string into the active window. \015 basically injects <enter>.

start screen using
screen -c multitop.screenrc 
and as usual,don't exit using exit or q, but use C+a - d to leave it running.


To make things a bit prettier and to enable users to reconnect to a running session, edit /etc/screenrc:

multiuser on
acladd me
defscrollback 5432
termcapinfo xterm|xterms|xs|rxvt ti@:te@
caption     always        "%{+b rk}%H%{gk} |%c %{yk}%d.%m.%Y | %72=Load: %l %{wk}"
hardstatus alwayslastline "%?%{yk}%-Lw%?%{wb}%n*%f %t%?(%u)%?%?%{yk}%+Lw%"

and
sudo chmod +s /usr/bin/screen
sudo chmod 755 /var/run/screen

If you start a session using e.g.
screen -S mytest
as user me

then other users can connect using
screen -x me/mytest