#! /bin/bash
i=0
while [ $i -lt 5 ] #While i is less than 5
do
echo "i is currently $i"
i=$[$i+1] #Not the lack of spaces around the brackets. This makes it a not a test expression
done #ends the loop
Watch that there are spaces around the brackets during the test (after the while statement). These spaces are necessary.
This loop outputs:
i is currently 0
i is currently 1
i is currently 2
i is currently 3
i is currently 4