How can I check if files exist but use a text file to house the file paths I am looking for?

I am using a batch script to install a client for state testing. I would like to verify that all of the files install correctly by checking to see that each one exists before creating an empty check file that tells the script it has already been installed, so don't install it again.

if exist filename. do TYPE NUL > testing_client.done

The above snippet works great if I'm just checking for a few files, but I'd like to verify a huge list of files.

In the interest of keeping my batch files easy to read, I'd love a way to use my text file that contains all of the paths/filenames that I need to check for instead of having to put those hundreds of lines into the batch file.

If it would help, I am willing to share more of the batch, but didn't want to make this post that long.

Any direction is appreciated!