How can I set up byobu to use a second screen session on login?

Question

tl;dr: I have an irssi proxy screen session running in the background. I'm running byobu -R -S byobu;exit in ~/.bash_profile to start a second session instead of reconnecting to the irssi session, but it starts a third session when I log in twice (e.g. once through the local terminal and once through SSH). How can I make the secon login reconnect to the first?

I had previously enabled byobu on login for my server. This worked fine, and I would get the same underlying screen session no matter where I logged in from.

However, then I added a second screen session to the server's boot:

[alex@alex-ubuntu-server ~]$ cat /etc/rc.local
#!/bin/sh -e
# [clipped out default ubuntu rc.local header]

# run an irssi proxy under screen as user alex
sudo -H -u alex screen -d -m -S irssi-proxy irssi

exit 0
[alex@alex-ubuntu-server ~]$ 

From then on, this command (which was put in my ~/.bash_profile by byobu configuration):

_byobu_sourced=1 . /usr/bin/byobu-launch -S byobu

would connect to the already existing irssi screen session, instead of creating a new session. This was obviously not ideal, so eventually I settled on the following command:

byobu -R -S byobu;exit

Then intention was to name the screen session, thus allowing a reconnect to the same name when I logged in again through e.g. SSH. However, when I login again, I get a fresh screen session instead of the existing one (as you can see in the example below, this has already happened once).

[alex@alex-ubuntu-server ~]$ screen -ls
There are screens on:
        18036.byobu     (07/07/2013 04:26:44 PM)        (Attached)
        3869.byobu      (07/05/2013 07:45:37 PM)        (Attached)
        1319.irssi-proxy        (07/04/2013 05:01:54 PM)        (Detached)
3 Sockets in /var/run/screen/S-alex.

[alex@alex-ubuntu-server ~]$ ssh localhost
Ubuntu 13.04
alex@localhost's password:
# at this point the screen redrew because of the new byobu session,
# so these weren't really one after another, as shown here
alex@alex-ubuntu-server:~$ screen -ls
There are screens on:
        6216.byobu      (07/07/2013 05:17:38 PM)        (Attached)
        18036.byobu     (07/07/2013 04:26:44 PM)        (Attached)
        3869.byobu      (07/05/2013 07:45:37 PM)        (Attached)
        1319.irssi-proxy        (07/04/2013 05:01:54 PM)        (Detached)
4 Sockets in /var/run/screen/S-alex.

alex@alex-ubuntu-server:~$ 

I'd prefer not to switch to tmux. How can I construct a byobu/screen command that reconnects to the existing second screen session if possible, but otherwise starts a new (second) session?

Answer 1

You could switch the irssi process to use tmux, instead of the login process.

Answer 2

When connecting using ssh to machine and you would like a new session you can create a new byobu session on connection (the -t flag is needed to "Force pseudo-terminal allocation" otherwise you can get the following error: "open terminal failed: not a terminal"):

ssh -t your_machine byobu new-session