Transfered from Linux Config:
Hi, How can I generate random number, preferably integer to be used within my bash script. Is there also a way to test whether random numbers are generated properly?
The easiest way on how to generate random number in bash is to use bash's $RANDOM function. $RANDOM is an internal Bash function that returns an integer in the range 0 - 32767.
For example the following line will generate 10 random integers in range from 1 to 10:
NOTE: +1 will simply shift result numbers from range 0 - 9 to 1 -10
Very basic test can be performed to see whether $RANDOM function creates a uniformly distributed random numbers. For this we would need more than 10 randomly generated numbers in order to see uniform distribution.
$ for i in $( seq 1 10 ); do echo int $i = $[ ( $RANDOM % 10 ) +1 ]; done
Therefore, we can create 100 000 random numbers from range 0 - 10 with modulus %11 and store them into file random.txt.
Using octave we can than generate a histogram with 11 bins to see whether bash $RANDOM internal function created uniformly distributed random numbers :
$ for i in $( seq 1 100000 ); do echo $[ ( $RANDOM % 11 ) ] >> random.txt; done