prepsim makes a simulation by taking out taxids and turning them into fake placements.
usage: prepsim [options] -c my.refpkg
| -c | Reference package path. Required. |
| --out-dir | Specify the directory to write files to. |
| --prefix | Specify a string to be prepended to filenames. Required. |
| -r | Comma-delimited list of tax_ids to prune. |