# How to run nested tmux session

[tmux](https://github.com/tmux/tmux/wiki) is a program that provides a convenient way for getting multiple terminal sessions into one window. If you are using it a lot, quickly you can find yourself asking for more - multilevel tmux. Example of nested tmux session:

[![asciicast](https://asciinema.org/a/424818.png)](https://asciinema.org/a/424818)

There are 2 settings necessary for this setup to work as expected. Inside `~/.tmux.conf` you need:
```
bind-key -n c-g send-prefix
bind-key -n c-t send-keys c-g
```

for prefix key access to nested windows. The default prefix is ctrl+b, so here I'm setting `ctrl+g` to work as prefix on the second level of tmux, and `ctrl+t` to work on the third level.

Thanks to configuration like this, if you use `ctrl+b` & `c` to create a new window on the first level of tmux, you will use:
* `ctrl+g` & `c` - to create window on the second level
* `ctrl+g` & `c` - to create window on the first

The other setting is inside your `.zshrc` or `.profile`:

```
unset TMUX
```

If we skip this, we will end up seeing:

```
$ tmux new -s test
sessions should be nested with care, unset $TMUX to force
```

# Summary
In this short guide, we have seen how to set up our tmux to support nesting with minimal configuration & nice mapping for prefix key. Let me know in the comments if you are interested.