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Making your $ more informative

June 06 2011

This is about your terminal prompt, not about money. Sorry to disappoint.

But seriously, I was watching a RailsCast earlier today and I noticed that the presenter was displaying his current git branch in his terminal prompt. I wondered "How can I do this?" So I asked Google. The first thing I tried was not exactly what I was looking for. I don't like having a bunch of pastel colors all over my terminal, and that the hostname, path, and username weren't quite in the order that I wanted. So I went back to my search results, and I found this. Here are the relevant bits:

export PS1=" "

Between the quotation marks, you can add the following lines to customize your Terminal prompt:

  • \d – Current date
  • \t – Current time
  • \h – Host name
  • \# – Command number
  • \u – User name
  • \W – Current working directory (ie: Desktop/)
  • \w – Current working directory, full path (ie: /Users/Admin/Desktop)

So then I combined the function from the first search result and came up with this:

parse_git_branch() {   git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/\[\1]/' } export PS1='\h:\w$(parse_git_branch) \u$ '

Which looks like this:

inglis-mac:~/intersect[work] drew$ [blinking cursor]

Now, recently I've been using RVM (both with Intersect and with other projects), and I decided that I wanted it to show up in the results, but only if I was using an environment other than system. This can pretty easily (if you remember that + cannot be used in sed regex) be accomplished by this function:

show_rvm_state() {   rvm current | sed -e 's/system//' -e 's/\(..*\)/[\1]/' #'..*' = '.+' on OSX }

The first bit kills it if it's system and the second bit puts it in brackets (so it looks pretty).

I also added a time function that only shows the hour and minute, so now my final everything looks like this:

parse_git_branch() {   git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/[\1]/' } show_rvm_state() {   rvm current | sed -e 's/system//' -e 's/\(..*\)/[\1]/' #'..*' = '.+' on OSX } short_time() {   date "+%H:%M" } export PS1='$(short_time) \h:\w$(parse_git_branch)$(show_rvm_state) \u$ '

If there's an easier way to do the "short_time" bit, let me know. I didn't want to spend too much time on this. I'm also thinking about taking out the system name and/or the username. What do you guys think?

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Drew writes code for fun and (sometimes) profit. He's currently studying Computer Science at Carnegie Mellon University. He has previously worked at Facebook, Amazon, and a startup called Intersect.