How to generate random numbers(chars) in linux shell script

In this article, we’ll learn how to generate random numbers or chars in linux shell script.

1. Environment

Centos7_x64

2. Generating random numbers in linux shell scripts.  

We can get a random 8-bit number by one of the following three methods scripts.

2.1. Use $RANDOM：

echo $RANDOM | cksum |cut -c 1-8

2.2. Use openssl:

openssl rand -base64 4 |cksum |cut -c 1-8

2.3. Use date:

date +%N | cut -c 1-8

Output figure

3. Generating random chars in linux shell scripts. 

We can get a random 8-bit char by one of the following three methods scripts.

3.1. Use $RANDOM

echo $RANDOM | md5sum | cut -c 1-8

3.2. Use openssl

openssl rand -base64 6

3.3. Use UUID

cat /proc/sys/kernel/random/uuid | cut -c 1-8

Output figure

From：Is Everything OK