Bash select example

I recently bought 2 raspberry pi computers. One is for home, and one is for the office.

Since we have dynamic IPs setup in the office, and I have the same at my house, I needed to be able to connect using the MAC address of the pi. I ended up writing a little script to get the IP based on the MAC Address, and then ssh into the computer. Pretty slick.

To make my life easier I used the select command in bash. The documentation for select leaves a lot to be desired. So I had to fiddle with it until I got it right. Here is a simple boilerplate for a bash script using select:

Function

#!/usr/bin/env bash

speak() {
  echo "$1 $2"
  break; # we are done
}
echo "What do you want me to say?"
select ab in "Hello" "Bonjour";
do
  case $ab in
    "Hello") speak "Hello" "my friend";;
    "Bonjour") speak "Bonjour" "mon ami";;
    *) echo "invalid option";; # you picked anything but 1 or 2
  esac
done

Save that in a file called say-hello.sh and change the rights to allow execution by using chmod +x say-hello.sh. Then you can run it:

Output:

$ ./say-hello.sh
  1) Hello
  2) Bonjour
  #? 1
  Hello my friend
$

You can see that in this example I push 1. If I run it again and push 2, you will see the French words show up.