At least 2-3 times a year I come across a very useful linux command line tool that I think to myself… "How did I not know about this tool, it's so useful!"
This is command 'shuf' is one of those tools.
I was writing a simple bash script last night to simply use curl to test out a restful service I am working on. It’s a restful service that accepts a POST of a JSON file. I wanted some of the number values in the JSON post to be randomized, something like 12.34 22.14 some floaty looking number within a narrow range.
Doing a quick google search I came across the command line tool shuf.
Here are a couple of main pages detailing shuf http://linux.die.net/man/1/shuf 
Here are some basic examples of what it can do.
> shuf -i 10-20
Will generate a list of the integers 10 to 20 inclusive and shuffle them up.
Or for my purposes I just wanted 1 number
> shuf -i 10-20 -n 1
Does the same thing but returns you a number in the shuffled list
> shuf -i 10-20 -n 3
Returns 3 numbers
For my base script I wanted to create a random number like 12.21 (it was not important that it be really random)
for ((i = 0; i < 20; i++))
num=`shuf -i 1-20 -n 1`.`shuf -i 1-99 -n 1`
Here are the results of the program running.
 shuf(1) - Linux man page
 shuf — generate random permutations