Tmux is a terminal multiplexer. Using tmux we can create, access and control terminals from a single terminal. Tmux sessions can be detached, continue running in the background, and then reattached. This is extremely helpful and it is one of the coolest features of tmux. To get up and running with tmux, you need to learn some tmux commands.
Every major distribution has tmux in their repositories, so you google them up. Below I listed the install commands for arch based and ubuntu distribution.
sudo pacman -Su tmuxsudo apt-get install tmuxbrew install tmuxTo start tmux, enter tmux in your terminal.
When tmux is started, it creates a single session with a single window in it. At the bottom, the status bar displays the information about the current session. If you don't like the look of tmux and want to customize the information displayed on the status bar, you can do that using a tmux config file, which we will see later in this series. Now, get out of tmux by typing exit.
To create a new tmux session, enter tmux new -s text-editor in your terminal. This will create a session named text-editor. In a session, you can create multiple windows. A window can have multiple panes. To achieve this, you need to know about the prefix key.
The default prefix key is ctrl+ b, that is you should press the ctrl and b keys simultaneously. Hereafter, I will refer the ctrl+b combination as prefix, so keep in mind.
To create a new window in your current session, type prefix c, this will create a new window and the focus will be on the newly created window. To navigate between the windows, use prefix p aka previous window and prefix n aka next window. Also, you can navigate through windows by using prefix [num] where num is the number associated with each window.
As I mentioned earlier, a single window can contain multiple panes. To create a vertical pane type prefix % (prefix key is ctrl+b). This will create a verical pane on the right side and the focus will be on the newly created window. To create a horizontal pane, type prefix ". If you find the key combination hard to remember and type, later in this series, you will learn how to change the default keybindings.
Now, we want our session continue to run in the background, so that we can later pick up where we left off. In tmux world, this is called attach and detach. To detach from our current session use prefix d. If you have detached from multiple sessions, you can see the list of all the sessions you have detached by entering tmux ls in your terminal. If you have a single session enter tmux attach in your terminal, you will be present at where you left off. Incase of more than one sessions listed in the output of tmux ls, you need to specify the session name like this tmux attach -t [session_name].
Additionally, if you don't want any of the sessionns to persist in the background, you can kill them using this command tmux kill-session -t [session_name].
As of now, you know how to create a new session, detach from a session, attach to a session, creating multiple windows and panes, it's time to configure tmux especially the keybindings, which you may find hard. Tmux looks for a configuration file in your home directory, so we need to create this file first.
touch ~/.tmux.confThe default prefix key is ctrl+b. To change this default binding, see the snippet below, where I am setting it to ctrl+a.
set -g prefix C-a
unbind C-bExit out of tmux and enter tmux again, to see the new prefix key in action.
Everytime you make changes to your config file, you need to reload it to see the effect. The below snippet does this. If you type prefix r, it will the reload the config and display the message "reloaded!" at the status bar.
bind r source-file ~/.tmux.conf \; "reloaded!"bind -r H resize-pane -L 5
bind -r L resize-pane -R 5
bind -r J resize-pane -D 5
bind -r K resize-pane -U 5Reload the file. Now, you can resize the panes using prefix and H,J,K,L keys. For example, if you have two horizontal panes and the focus is on the top pane, you can increase its size by pressing prefix J. H for left, L for right, J for down and K for up.
bind | split-window -h
bind - split-window -v
unbind '""'
unbind %After reloading, you can use prefix | for vertical split and prefix - for horizontal split.
# for panes
bind -n M-Left select-pane -L
bind -n M-Right select-pane -R
bind -n M-Up select-pane -U
bind -n M-Down select-pane -D
# for windows
bind-key -n C-Right select-window -n
bind-key -n C-Left select-window -pAfter reloading the file, you can navigate between windows using Ctrl+Left and Ctrl+Right keybindings. For panes, use the Left Alt key with ARROW KEYS.
By default, the windows and panes will be numbered starting from 0 which feels strange. The following snippet can be used to set the index start from 1.
set -g base-index 1
setw -g pane-base-index 1When you open a new window or split a pane, if you feel that the response is not fast enought, you can set the escape-time value to 1and immediately feel the snappiness of tmux.
set -sg escape-time 1Status bar can be customized to display some useful information. On the left side we can display information such as session name, window number and pane number. On the right side, we can set it to display to battery precentage, date and time. For the right side panel, we can use the tmux plugin tmux-battery
git clone https://github.com/tmux-plugins/tmux-battery# Status bar customization
set -g status-left-length 40
set -g status-left "#[fg=green]#S #[fg=yellow]#I #[fg=cyan]#P "
# Right panel: Display battery, Date, Time
set -g status-right 'Batt: #{battery_percentage} | %a %h-%d %H:%M 'The following line should be at the bottom of your config file. This line points to the location of the file battery.tmux which is lacated in the repo you cloned earlier.
# These commands should be at the bottom!
run-shell ~/Downloads/tmux-battery/battery.tmuxYou should rename your window so that you can quickly see what process are taking place in each window by looking at the window name. Press prefix , and it will prompt you to enter the window name.
Splitting the windows into multiple panes is a neat feature, sometimes you just want to focus on working only on one pane, for that press prefix z to zoom the pane and again press the same keybinding to revert back'
You can close the windows and panes by entering exit but if you want to do it in the tmux way, press prefix & to close the window and enter y in the prompt for confirmation.
Similarly, for panes press prefix x.
Tmux has some default pane layouts that you maybe interested in. You can cycle through the pane layouts by pressing prefix spacebar.
You can get the list of all the available keybindings in tmux by pressing prefix ? and press q to exit out of it.
Yes, tmux has command mode, isn't it awesome? You can access command mode by pressing prefix : and it will prompt you to enter the commands. See the below snippet.
new-window -n text-editor "vim"The above command does what is says, i.e, it creates a new window named text-editor and opens vim in it.