byobu will not start after upgrade: Cannot exec 'motd+shell'

So symlinking motd+shell definitely fixes the issue on upgrade. However it wouldn't fix the following situation:

A user who uses a tty does the following:
1) Makes changes that have the effect of changing the contents of .byobu/windows to something similar to:

# Default windows examples
#screen -t notify-osd -M tail -f $HOME/.cache/notify-osd.log
#screen -t top top
#screen -t web elinks
#screen -t shell motd+shell
screen -t opps does_not_exist

2) User has launch on login check.
3) User logs out.
4) User logs in.
5) User is immediately logged out when does_not_exist fails to exec.

I'm not sure if there is really anything that can be done about this or if it is really a bug. I just thought I should mention it. I've tested this situation on my Ubuntu desktop, and am not sure how it would play out on ubuntu-server yet.

Well, that would be unfortunate. It might occur if the user typo's
the line in the windows file.

I'd recommend something along the lines of:
 ssh <machine> rm -f ~/.byobu/windows

That does of course require ssh access.

Actually, this should already be fixed the current 2.79 release.

This now puts the following in ~/.profile:
`echo $- | grep -qs i` && byobu-launcher && exit 0

That "&& exit 0" should only exit if the byobu command succeeded. If
it exited non-zero, I think it should drop you to a command prompt.
Can you give that a shot?

I'm still seeing the error with the following:

$ apt-cache policy byobu
byobu:
  Installed: 2.79-0ubuntu1~ppa4
  Candidate: 2.79-0ubuntu1~ppa4

$ cat .byobu/windows
# Default windows examples
#screen -t notify-osd -M tail -f $HOME/.cache/notify-osd.log
#screen -t top top
#screen -t web elinks
#screen -t shell motd+shell
screen -t shell /bin/does_not_exist

1) Switch to tty1 (Ctrl + Alt + F1)
2) Login
3) Get a message about the inability to exec
4) Screen terminates and I am logged out.

The problem is that byobu is exiting with 0.

This can be seen if you do the following from a terminal with the
errant .byobu/windows file:

$ byobu
(Unable to exec, screen terminates)
$echo $?
0

Similarly,

$ screen does_not_exist
(unable to exec, screen terminates)
$ echo $?
0

Hmm, I'm not sure what else we can do within byobu here.

Perhaps we need to patch screen to propagate the command-not-found
error message and exit code.

I had a few minutes today and created a semi-solution here:

https://code.edge.launchpad.net/~ssd7/byobu/byobu-newwindow-check

It's not truly a solution, but it checks to ensure that the command given in the new window dialog is executable. At the very least this would prevent byobu-config from ever writing a .byobu/windows file that leads to this situation.

Thanks, Steven, I'll have a look.

Thanks, Steven.

I fixed the particular bug in the initial report. I did take a look at your branch (thanks!). I don't think that's quite the best solution, though (running of the command). We don't really know what that command is, or if the user *actually* wants to run it. It might be a really long, hard, difficult operation, or even something that is only supposed to be run once, or occasionally.

Anyway, hopefully the main issue (upgrading when motd+shell doesn't exist) is solved now, though :-)

Cheers,
:-Dustin

This bug was fixed in the package byobu - 3.2-0ubuntu1

---------------
byobu (3.2-0ubuntu1) maverick; urgency=low

  * usr/share/byobu/keybindings/f-keys: resize the screen as part of the
    F5/refresh, LP: #619899
  * usr/bin/byobu-launcher: don't launch if in a dumb terminal, LP: #612886
  * usr/lib/byobu/network, usr/share/man/man1/byobu.1: allow for
    configuration of network traffic in [kM]ps, LP: #578377
  * configure.ac: POSIX sed doesn't include -i option, LP: #619328, #622640
  * usr/bin/byobu-janitor: improve dash replacement in status config,
    LP: #598488
  * usr/bin/byobu-janitor: fix upgrades where one's window list might have
    motd+shell, LP: #589715
 -- Dustin Kirkland <email address hidden> Mon, 23 Aug 2010 17:34:33 -0400