How to use dictionary input but first convert to sha256

I would like to know how to use passphased sha256 as dictionary input.

So i have a txt files with passphrases which need to be converted to sha256sum, this output is then used in hashcat.

I could convert the whole txt file to sha256 first but I want to use the rule files as well..

Any ideas?
what the fuck did i just read?

edit: try
xargs -I_ sh -c 'echo -n "_" | sha256sum' <<(cat wordlist) | cut -d\  -f1