Ever wanted to add some randomness to your shell script? No I don’t mean to make them flaky!
Unix shells provide a $RANDOM environment variable that we can use in our shell commands or scripts:
% echo $RANDOM
21290
% echo $RANDOM
8367
The seed for the random number generator can be changed as follows:
% RANDOM=12345
% echo $RANDOM
5758
Generating random numbers in a range
We can use awk for generating random integers in a given range. For example, to generate a random number between 1 and 10 (inclusive):
% awk -v seed=$RANDOM 'BEGIN{srand(seed); print int(rand()*10+1)}'
10
% awk -v seed=$RANDOM 'BEGIN{srand(seed); print int(rand()*10+1)}'
4
% awk -v seed=$RANDOM 'BEGIN{srand(seed); print int(rand()*10+1)}'
1