I'm writing a shell script that creates / attaches or switches to a given session, depending on whether one is inside tmux and the session exists.
I've got everything working great except for the case requiring the creation of a new tmux session from within a tmux session.
When my script executes tmux new-session -s name, I get the following output:
sessions should be nested with care, unset $TMUX to force
I don't actually want to nest sessions, my goal is to create another separate session and switch to it from within a tmux session.
Is this possible?
16 Answers
The quickest way (assuming you use ctrl-b as your command prefix) is:
ctrl-b :newTo create a new session, then
ctrl-b sto interactively select and attach to the session.
4How to create the script
This script will check if a session exists. If session does not exist create new session and attach to it. If session does exist nothing happens and we attach to that session. Feel free to replace `~/development' with project name.
$ touch ~/development && chmod +x ~/development
# ~/development
tmux has-session -t development
if [ $? != 0 ]
then tmux new-session -s development
fi
tmux attach -t development New session from terminal
Let's create two detached sessions, list them, attach to one and then from within tmux cycle through sessions.
tmux new -s name -d works from inside tmux because we're creating a new detached session. Otherwise you'll get a nesting error.
$ tmux new -s development -d
$ tmux new -s foo -d
$ tmux ls
> development: 1 windows (created Wed Jan 13 11:31:38 2016) [204x54]
> foo: 1 windows (created Wed Jan 13 11:31:38 2016) [204x54]
$ tmux attach -t
$ tmux ls
> development: 1 windows (created Wed Jan 13 11:31:38 2016) [204x54] (attached)
> foo: 1 windows (created Wed Jan 13 11:31:38 2016) [204x54]New session from within tmux
We are now inside or better known as attached to our target session. If we try to create a new session while attached it will result in a nesting error.
$ tmux new -s bar
> sessions should be nested with care, unset $TMUX to forceTo solve this we create a new detached session. e.g.,
$ tmux new -s bar -d
$ tmux ls
> development: 1 windows (created Wed Jan 13 11:31:38 2016) [204x54] (attached)
> foo: 1 windows (created Wed Jan 13 11:31:38 2016) [204x54]
> bar: 1 windows (created Wed Jan 13 17:19:35 2016) [204x54]Cycle (switch) Sessions
Prefix(previous sessionPrefix)next session
note: Prefix is Ctrl-bby default. You can bind Prefix to Ctrl-a and in Mac OSX you can change Caps Lock to ctrl system preferences > keyboard > modifier keys
Attach to a session using command mode while inside tmux
Trying to attach to a session without detaching will result in an error.
$ tmux attach -t development
> sessions should be nested with care, unset $TMUX to forceInstead use command mode Prefix : then type attach -t session_name and hit enter.
Using this works for me:
TMUX= tmux new-session -d -s name
tmux switch-client -t nameThe TMUX= on the first line is required so tmux doesn't throw a sessions should be nested with care, unset $TMUX to force message.
All the commands you can launch within your terminal, like tmux new -s sessionName can be launched from within tmux by pressing the trigger key (eg: ctrl-b) then : then the command without the starting tmux part.
As a result, ctrl-b : followed by new -s sessionName will do exactly what you want and give a name to your session. It also switches automatically to the new session.
You can try unset TMUX first, this works for me.
at user2354696's advice I use following key bindings to create a new session or "clone" an existing session
bind-key N run-shell 'TMUX= tmux new-session -d \; switch-client -n' bind-key C run-shell 'TMUX= tmux new-session -t $(tmux display-message -p #S) -s $(tmux display-message -p #S-clone) -d \; switch-client -n \; display-message "session #S cloned"'
