Loop

For GRUB scripting language, looping in GRUB is very crude and simple. Keep in mind that GRUB does not have arithmetic functionalities. Hence, you can't do something like $((count - 1)) in POSIX shell. It's best to keep it to a Boolean type conditions.

You can use the following to control the loop actions:

• continue - skip this loop and proceed to the next one
• break - exit the loop immediately

For Loop

You can use for loop for predictable looping.

Basic

The very basic format is similar to POSIX version:

grub> for i in 1 2 3; do

> echo "current: $i"

> done

current 1

current 2

current 3

grub>

In script form:

for i in 1 2 3; do

        echo "current: $i"

done

While Loop

You can use while loop for unpredictable or conditional looping. Keep in mind that GRUB does not have arithmetic functionalities. Hence, you can't do something like $((count - 1)) in POSIX shell. It's best to keep it to a Boolean type conditions.

Basic

while [ controllable Boolean type conditions ]; do

        ...

done

Until Loop

You can use while loop for unpredictable or conditional looping. Keep in mind that GRUB does not have arithmetic functionalities. Hence, you can't do something like $((count - 1)) in POSIX shell. It's best to keep it to a Boolean type conditions.

Basic

until [ controllable Boolean type conditions ]; do

        ...

done

That's all about looping in GRUB scripting language.