bash has three types of loop constructs
– for
– while
– until

until loop is used to iterate over the body of the loop till the condition stays false.

syntax:

until [ condition ];
do
  block-of-statements
done

example:

#!/bin/bash
echo “example of until”
i=20
until [ $i == 1 ]; do  # condition stays false
  echo "${i} is still greater than 1”
  i=$((i-1))  # i = i - 1
done
echo “value of i = ${i}"

You may chose to throw this code in a shell script and see it go.