Assign the result of a command to a variable in a bash script

Mon Aug 24 2020

I do not write bash scripts anywhere near often enough to recall the basics so I inevitably lose time searching for answers. In this case I failed to understand how to assign the result of a command to a variable.

All I wanted to do was assign a random number to a variable like so…

#!/bin/bash

RANDOM_NUMBER=jot -r 1 2000 65000
echo $RANDOM_NUMBER

This results in the following output when you run this script…

$ ./my-script.sh
./my-script.sh: line 3: -r: command not found

To assign the result of the command to the variable RANDOM_NUMBER there are 2 approaches…

Wrap the command in $()

#!/bin/bash

RANDOM_NUMBER=$(jot -r 1 2000 65000)
echo $RANDOM_NUMBER

Wrap the command in backticks

#!/bin/bash

RANDOM_NUMBER=`jot -r 1 2000 65000`
echo $RANDOM_NUMBER

Everyday I feel like a beginner. I found the answer here should you want to explore further.