tmux SSH Session – Cannot Connect to X Server

sshtmuxx11

At work, I have a desktop with a monitor and a few running tmux sessions. At home, I frequently ssh into that desktop and enter my running tmux sessions. When I ssh from home, I do not want to use X11, so I do not use the -X flag. When I go back to work (after ssh'ing from home) and use those tmux sessions on desktop, I can no longer do anything that would spawn a GUI. I can't open files in evince. When I try use matplotlib, I get a : cannot connect to X server message.

After ssh'ing and opening an existing tmux session from home, how do I later reattach the ability to open up GUI stuff on the desktop?

The ssh'ing from home seems to make the tmux session forget that it can spawn GUI stuff.

EDIT:

Best Answer

I had the same issue. I normally use tmux as part of a multi-monitor X11 desktop environment, and sometimes ssh in from a chromebook, which doesn't support X11 or set $DISPLAY. The answer by @chrisdembia works, but requires changing DISPLAY in each new window for the rest of the tmux session, which is a pain.

A permanent solution is to remove DISPLAY from the tmux update-environment variable in the tmux settings. You can see your current value with this command:

tmux show-options -g update-environment

To remove it, I added this line to my ~/.tmux.conf file, including everything but DISPLAY:

set-option -g update-environment "SSH_ASKPASS SSH_AUTH_SOCK SSH_AGENT_PID SSH_CONNECTION WINDOWID XAUTHORITY"

This is further explained at Reset the shell DISPLAY variable in a tmux session over ssh, which explains why DISPLAY is there by default, for a different common use case.

Related Solutions

Tmux: Set default session for attach

It is time sensitive.

From the man page:

The target-session rules for attach-session are slightly adjusted: if tmux needs to select the most recently used session, it will prefer the most recently used unattached session.

Your shell alias is the way to go for this, it is not a workaround, but the way Unix/Linux works. Small tools to do small things to produce great results.

When exiting the last terminal in a tmux session can it switch to another

The closest I got was a tmux function I wrote. I normally exit the shell by hitting Ctrl+D, so I programmed tmux to exit and switch sessions when hitting [PREFIX] Ctrl+D. Put the following in your .tmux.conf:

bind C-d run-shell "                                        \
    if [ #{session_windows} -eq 1 ] &&                      \
       [ #{window_panes}    -eq 1 ] &&                      \
       [ #{pane_current_command}  = 'bash' ]; then          \
        if [ \$(tmux list-sessions | wc -l) -ge 2 ]; then   \
            tmux switch-client -ln;                         \
        fi; tmux kill-session -t \"#S\";                    \
    else                                                    \
        tmux display-message \"Ignoring kill session...\";  \
    fi;                                                     \
    "

Hit [PREFIX] Ctrl+D and it exits the current session if (and only if) it holds only one shell which is not running any other commands. It will switch to another session if possible. I use the bash shell, so you might need to change it to something you are using.

ps: in case it matters, I'm currently using tmux 1.9a.

Best Answer

Related Solutions

Tmux: Set default session for attach

When exiting the last terminal in a tmux session can it switch to another

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