title: Bash Generate a random number between a positive and a negative
body: <p>I have to write a Program, which shows some words on an image which are randomly rotated. I would like these to be between e.g -30 and 30 ° .  But I didn't found any command in bash/UNIX, that could generate a random number between a positive and a negative.</p>
  
  <p>Thanks for your help.</p>