Tmux is one of the most useful tool when it comes to using a linux terminal.

Tmux is a terminal multiplexer, it allows a user to access multiple terminals (or windows), each running a separate program, while providing a single screen to work on. Tmux is useful for running more than one command-line program at the same time, increasing productivity and the way you work.

In case you are seeing the error -

tmux: open terminal failed: missing or unsuitable terminal: xterm-256color

It means that you don't have the terminal xterm-256color. There may be several reasons for it, here are solutions how you can fix it.

First Solution,

1. Restart tmux

You will need to kill tmux server and start is back.

tmux kill-server

and then, open tmux again by running the tmux command-

tmux

Second Solution,

2. Set TERM to xterm

Try to set the value of TERM to xterm in your ~/.bash_profile file

export TERM=xterm

Third Solution,

3. Install xterm-256 from another system

In case you are absolutely looking for

Prefix
:set -g mouse on

By default the prefix is Ctrl-B

Ctrl-B
:set -g mouse on

You can also make this a default behaviour of tmux, by adding the setting in ~/.tmux.conf-

set -g mouse on

After adding the above line to the configuration file, you can reload tmux conf-

tmux source-file ~/.tmux.conf

I hope steps to fix the color issue was useful. You can also check out the complete tmux cheatsheet of keyboard shortcuts and mouse shortcuts.