#!/bin/bash

# while [ condition ]; do
#   [Commands]
# done

num=1
until [ $num -gt 10 ]; do
  echo $(($num * 3))
  num=$(($num+1))
done

# 3
# 6
# 9
# 12
# 15
# 18
# 21
# 24
# 27
# 30