I’m a member of this amazing online community called Virtual Coffee. We meet twice a week and have conversations about the tech industry as well as tech-adjcent topics. In today’s meeting, we kept coming back to reducing project anxiety by breaking large tasks down into several smaller ones. I kept thinking of a quote I like that illustrates this:

The person who removes a mountain begins by carrying away small stones. —Chinese Proverb

In fact, I have a whole file of quotes I pick up here and there that bring me joy and inspiration. I’ve created a bash script that outputs one quote from this file at random every time I open a new terminal. After sharing this with my Virtual Coffee group, they were eager to learn how I did it, so here’s a step-by-step write up for you to create a random quote generator of your own!

The Script

Add the following code inside the prompt function in your .bash_profile file, just above the line where you define export PS1:

function prompt {
  sed -n $(awk "END{ print $RANDOM%NR+1}" $quote)p $quote
  export PS1

And that’s all. It’s that simple!

My terminal prompt

A Breakdown of the Above

The quote variable is a path to the simple text file where my list of quotes are stored. Depending on your editor (I use Mac’s default, TextEdit), the quotes may wrap. That’s okay as long as you start each new quote on a separate line.

Edge Case: Leave a blank new line at the end of your text file. If the last quote in your file is randomly selected, the PS1 in your terminal will appear on the same line directly after the quote if you don’t do this!

This snippet awk "END{ print $RANDOM%NR+1}" $quote is actually using the AWK scripting language! This denotes that we’re executing the action { print $RANDOM%NR+1} for the pattern END on the file represented by the variable $quote (as defined on the line above it). END counts the number of lines in the entire $quote file. Then NR returns the specified row number, which in this case is that of the last line as denoted by END, and the result of $RANDOM%NR+1 is printed out. $RANDOM is a built-in bash variable that returns a random integer, which we use as the numberator to NR’s denominator to return to remainder using the modulo operation (%).

Edge Case: After the remainder is calculated, we increment by one. Doing this accounts for a remainder of zero and ensures that a quote will always be returned.

Do you see how that whole code snippet is encapsulated in $()? Let’s take the number we just returned and assign it to the variable modulo for the rest of this breakdown.

Now what we’re left with is sed -n $(modulo)p $quote. sed isn’t bash—sed is actually a Unix utility called a stream editor! And like AWK, we can pass it options before passing the input file. By default, sed prints out all processed input so we use -n to suppress output and p to print specific lines. We already know from above that modulo is a random number that maps to the number of lines in your quote text file, therefore, you should see a random quote from your file print to the terminal!

I also have a pretty little bash prompt that shows me where I am in my directory, has custom colors, and displays git repos and branches. If you want to know more about this setup, DM me on Twitter @meg_gutshall!