# A Couple Ways to Return a Random Number on the Command Line

Lets explore a couple ways to get random numbers on the command line.

Anyone who attempts to generate random numbers by deterministic means is, of course, living in a state of sin.

John von Neumann

`$RANDOM`

Bash Internal

`$RANDOM`

is an internal Bash function (not a constant) that returns a pseudo-random integer in the range of 0 - 32767.

```
echo $RANDOM
8437
echo $RANDOM
29923
```

Getting a random number between `1 - X`

, or `0 - (X-1)`

.

```
X=10
echo $[RANDOM%X+1] # return number between 1 and 10
8
echo $[RANDOM%X] # return number between 0 and 9
3
```

## Kernel Entropy

A random number from 1 - 256 using kernel entropy:

```
od -An -N1 -tu1 /dev/random
181
```

All sorts of options.