Empty Body For Loop Linux Shell

Question

Hi I want to write and empty body loop. I just want the loop counter to increment so I want the cpu to stay busy without any IO operation. Here is what I have written but it gives me an error:

#!/bin/bash
for ((  i = 0 ;  i <= 1000000;  i++  ))
do
done


root@ubuntu:~# ./forLoop
./forLoop: line 4: syntax error near unexpected token `done'
./forLoop: line 4: `done'

Answer 1

You must specify at least one command in a loop body.

The best comand fo such purposes ia a colon :, commonly used as a no-op shell command.

Answer 2

You could put a no op command inside the loop like true or false (do nothing successfully or unsuccessfully respectively).

This will be a tight loop and will burn CPU. Unless you want to warm up your computer on a cold morning, you can simply say i=1000000 and have the same effect as the loop.

What is it that you're trying to achieve?

Answer 3

#!/bin/bash
let i=0 
while [[ $i -le 1000000 ]]; do
  let i++ 
done