Wednesday, August 14, 2013

How to customize your terminal prompt (with colors)

At work, the Go projects we're working on have workspaces that get pretty deep and one of the directory names is repeated down the tree. I ended up having no room to type commands in my terminal that didn't wrap to the next line. Annoying!

I could have just limited the prompt to show me the name of the current directory and use pwd when needed, but that was kind of a pain. Then I watched this talk and saw his terminal, and got inspired.

So here's my terminal and prompt now:

Customized terminal prompt -- the red "root" text blinks as a warning/reminder
Doing this took a while to figure out (especially the colors, and getting the root user to share the look). It's a simple idea: edit your ~/.bash_profile file and specify the PS1 variable.

Here's how I did it (this works in both my Mac and Raspberry Pi):

case `id -u` in
    0) export PS1="$Decoration1$RootUserPart$Between$HostPart$PathPart$Decoration2# ";;
    *) export PS1="$Decoration1$RegularUserPart$Between$HostPart$PathPart$Decoration2$ ";;

Each segment that looks like \[\e[90m\] changes the color and attributes of the following text, according to an enumeration like this one. The following text keeps those settings until you change it again or reset it. The number before the m is the color. Sometimes there's a number, semicolon, and another number. The second number in that case specifies underline, bold, blink, etc. You can omit both entirely to reset the text to its default or previous style.

To get the root user to share the style, you can, if on a Mac, put that code in your /etc/bashrc file, or on any Linux system (including RPi), you can have the root user's .bashrc source your own .bashrc file. A simple line similar to the following should do the trick (include the dot at the beginning of the line; or you can replace it with source):

. /home/pi/.bashrc

You may also like to have a blank line before each prompt to make it feel a little more "roomy" and less cluttered. You can easily do this by adding \n at the beginning of the $Decoration1 value.

I've really enjoyed this new prompt style. I have plenty of room to type, can clearly see my user, hostname, and current path at a glance. My prompts don't get lost in lots of output (like a disastrous g++ compile).

You're welcome to use it and customize it however you'd like. I'd be interested to see what you come up with.