convex_taxids determines convex tax_ids per-rank in a refpkg.
usage: convex_taxids -c my.refpkg
| -c | Reference package path. Required. |
| -o | Specify the filename to write to. |
| --out-dir | Specify the directory to write files to. |
| --prefix | Specify a string to be prepended to filenames. |
| --no-csv | Output the results as a padded matrix instead of csv. |