That was close. I think you want to do:
sha256sum * > shasum.txt
Edit: if you got subfolders, then something like that should work:
find myFolder -type f | xargs sha256sum > shasum.txt
or in the folder:
find . -type f | xargs sha256sum > shasum.txt
if you want only some files you can filter with -name
:
find . -type f -name "*.wav" | xargs sha256sum > shasum.txt
if you have filenames with newlines or strange things, you can use -print0
:
find . -type f -print0 | xargs -0 sha256sum > shasum.txt