Can't resume screen, says I am already attached?

  • I am working on a remote Debian Jessie server. I have started a screen session, started running a script, then been disconnected by a network timeout.

    Now I have logged in again and want to resume the session.

    This is what I see when I list screens:

    $ screen -ls
    There are screens on:
        30608.pts-8.myserver    (11/03/2015 08:47:58 AM)    (Attached)
        21168.pts-0.myserver    (11/03/2015 05:29:24 AM)    (Attached)
        7006.pts-4.myserver (10/23/2015 09:05:45 AM)    (Detached)
        18228.pts-4.myserver    (10/21/2015 07:50:49 AM)    (Detached)
        17849.pts-0.myserver    (10/21/2015 07:43:53 AM)    (Detached)
    5 Sockets in /var/run/screen/S-me.
    

    I seem to be attached to two screens at once.

    Now I want to resume the session I was running before, to see the results of my script:

    $ screen -r 30608.pts-8.myserver
    There is a screen on:
        30608.pts-8.OpenPrescribing (11/03/2015 08:47:58 AM)    (Attached)
    There is no screen to be resumed matching 30608.pts-8.myserver.
    

    Why I can't I re-attach?

    I have the same problem with the other screen:

    $ screen -r 21168.pts-0.myserver
    There is a screen on:
        21168.pts-0.OpenPrescribing (11/03/2015 05:29:24 AM)    (Attached)
    There is no screen to be resumed matching 21168.pts-0.myserver.
    
  • The session is still attached on another terminal. The server hasn't detected the network outage on that connection: it only detects the outage when it tries to send a packet and gets an error back or no response after a timeout, but this hasn't happened yet. You're in a common situation where the client detected the outage because it tried to send some input and failed, but the server is just sitting there waiting for input. Eventually the server will send a keepalive packet and detect that the connection is dead.

    In the meantime, use the -d option to detach the screen session from the terminal where it's in.

    screen -r -d 30608
    

    screen -rd is pretty much the standard way to attach to an existing screen session.

    To attach to an existing screen session, it's `screen -x`, `screen -rd` is to attach to it after having detached it from *every* terminal it was attached to. In the case of the OP, I'd agree the latter is probably prefered, but in the general case, not necessarily. I generally use `-xR` to attach or create if there's nothing to attach.

License under CC-BY-SA with attribution


Content dated before 6/26/2020 9:53 AM