$ gemmi json2cif -h
Usage:
 gemmi json2cif [options] INPUT_FILE OUTPUT_FILE

Convert mmJSON to mmCIF.

Options:
  -h, --help           Print usage and exit.
  -V, --version        Print version and exit.
  -v, --verbose        Verbose output.
  --pdbx-style         Similar styling (formatting) as in wwPDB.
  --cif2cif            Read CIF not JSON.
  --skip-category=CAT  Do not output tags starting with _CAT
  --sort               Sort tags in alphabetical order.

When output file is -, write to standard output.