until loop
The until loop executes the commands between the do and done statements as long as the tested condition is false. Here is the syntax:
until [conditional-expression]
do
commands
done
Here is a simple example:
NUM=0
until [ $NUM == 5 ]
do
echo “The number is $NUM.”
let NUM=$NUM+1
done
In the example above you can see that the until loop executes until the value of the NUM variable becomes 5: