# Python package or CLI tool outputting mutations of sequence with respect to reference

I'm new to bioinformatics, and I'm looking for a tool that takes two FASTA files, one containing a reference, let's call it A.fasta, the other another sequence, let's call it B.fasta, and outputs just the mutations that B contains with respect to A.

I'm open as to the output format. Is there a standard for this?

Background: I'm trying to analyse Sars-CoV-2 sequences and identify mutations with respect to the reference. I've done a google search for a tool that does what I want to but couldn't find something straightaway. Is there no standard tool for this?