Macbook battery status in tmux

Note: this post was migrated from my old Tumblr-backed blog

For the last couple of weeks, I’ve been using tmux more and more and I have to say that I really like it. For those that don’t know, tmux is a very scriptable “terminal multiplexer.” What this means is that you can create multiple virtual terminals in a single session and even arbitrarily split the window to run multiple applications in the same session. I like it a lot more than screen in that it just has a better overall feel and I don’t think I can live without it.

After discovering iTerm2 and moving away from MacVim, towards straight-up vim, and going full-screen with my terminal, I noticed one thing that I was missing, and that was being able to see my battery status. When iTerm2 full-screens, I lose my menu bar and once I start worrying about my battery status, I find myself obsessively moving the mouse to the top of the screen to display my menu bar to check the battery.

In walks batt.

batt is a commandline script that will display information about your Macbook’s battery. This includes whether it’s plugged in, how much time is left and what the % capacity is. I packaged it as a gem for easy distribution and released version 0.1.0 today.

Currently, batt only supports OSX and has only been tested in 10.8 Mountain Lion.

To install batt, you can run the following in your terminal:

gem install batt

If you’re not running rvm, you may have to use sudo to install it.

From there, you now have access to batt and can get all kinds of information about your battery; for example:

batt all

will spit out:

source: Battery Power
capacity: 30%
status: discharging
remaining: 1:16 remaining


batt capacity

will spit out


For tmux, I added a --tmux switch to the capacity action to add some colour to the output, so you can use it in your status line. My current tmux.conf contains the following lines:

set-option status-right-length 120
set-option status-right "[ #(batt source) #(batt capacity --tmux) ] #(date \"+%Y-%m-%d %H:%M\")"

You can read more in the readme on the project page:

Please, let me know what you think of the project and I’m open to any kind of code contributions or ideas.