While loop to test if a file exists in bash

Question

I\'m working on a shell script that does certain changes on a txt file only if it does exist, however this test loop doesn\'t work, I wonder why? Thank you!

Answer 1

works with bash and sh both:

touch /tmp/testfile
sleep 10 && rm /tmp/testfile &
until ! [ -f /tmp/testfile ]
do
   echo "testfile still exist..."
   sleep 1
done
echo "now testfile is deleted.."