Question

So, basically the code below is giving an infinite loop. However, if i change i+2 and f+2 to i++ and f++, they don’t give an infinite loop. Can someone explain to me why this is? Thanks

#!/bin/bash
for ((i=0; i<5; i+2))
do
for ((f=0; f<5; f+2))
do
echo "$i $f"
done
done

Answer 1

You need to do +=, not + (also, i+=2 should be f+=2 in your inner loop):

for ((i=0; i<5; i+=2))
do
    for ((f=0; f<5; f+=2))
    do
        echo "$i $f"
    done
done