Is there a tmux equivalent of “screen -D -R”

Question

I would like to know if there is a way to get tmux to behave like screen -D -R so I could say, have the command as a default command in Putty.

These screen switches would force detach of an existing screen session for my user (even if it was still active and logged-in somewhere else) and reattach it to the current session. Also, in the case that no screen session existed, it would create a new one.

I like tmux and can see clear benefits over screen, but the existence of this feature would really seal the deal.

tmux attach doesn't seem to create a new session if there isn't one.

The man page for tmux says:

If no server is started, attach-session (attach) will attempt to start it; this will fail unless sessions are created in the configuration file.

I'm not sure exactly what the section in bold means: I can't find an example of creating a session in the conf file.

Any suggestions?

Thanks.

Answer 1

To make tmux attach create a new session when there isn't one, use the option new-session in the tmux config file. Create the file ~/.tmux.conf if it doesn't exist, and add

new-session

to it. Also, I alias tmux to tmux attach :)

Answer 2

Yes:

$ tmux attach -d || tmux new

-d is necessary to behave like screen -D, ie, detach everybody else.

Connect by ssh, then attach or create could be something like:

$ cat bin/stmux
#!/bin/sh
exec ssh -t $@ 'tmux attach -d || tmux new'
$ stmux my.remote.box

Answer 3

You can emulate this with a shell function, this should work for any POSIX-compliant shell:

tmux() {
    if [ "$#" -ge 1 ] && [ "$1" = -z ]; then
        shift
        command tmux detach 2>/dev/null
        command tmux attach "$@" || command tmux new-session "$@"
    else
        command tmux "$@"
    fi
}

Now if you launch it as tmux -z, it should perform the actions you're looking for.