Question

I am making a script that needs to loop over a list of files named
like file1, file2, file3, all named the same with the suffix number increasing
according to users input.

So I made thia script, but when I input number 3, she loops only
over file1 and it stops.
Why?

How do I make it loop over n files according to users input?

This is my script:

    #!/bin/bash
    echo "Base name of machines to bring down:"
    read vm
    echo "Number of machines:"
    read num

    COUNTER=0
    while [  $COUNTER -lt $num ]; do
      num=$[$COUNTER+1]
      VBoxManage controlvm $vm$num poweroff
      let COUNTER=COUNTER+1
    done

Answer 1

use double paren for arithmetic:

#!/bin/bash
echo "Base name of machines to bring down:"
read vm
echo "Number of machines:"
read num

let COUNTER=1
while ((  COUNTER <= num )); do
    echo $COUNTER of $num
    let COUNTER=COUNTER+1
done

Update

I fixed the script so the counter starts at 1 instead of 0. It seems @toninoj wants to start at 1, but in his script, he started at 0.