Split a 10xscATAC bam file by cluster

I want to split the PBMC scATAC bam from 10x by cluster id. So, I can then make a bigwig for each cluster to visualize in IGV. The first thing I did was googling to see if anyone has written such a tool (Do not reinvent the wheels!). People have done that because I saw figures from the scATAC papers. I just could not find it. Maybe I need to refine my googling skills.

How to make a transcript to gene mapping file

I need a transcript to gene mapping file for Salmon. I am aware of annotation bioconductor packages that can do this job. However, I was working on a species which does not have the annotation in a package format (I am going to use Drosphila as an example for this blog post). I had to go and got the gtf file and made such a file from scratch. Please read the specifications of those two file formats.