$ gemmi reindex -h
Usage:
  gemmi reindex [options] INPUT_MTZ OUTPUT_MTZ
Options:
  -h, --help      Print usage and exit.
  -V, --version   Print version and exit.
  -v, --verbose   Verbose output.
  --hkl=OP        Reindexing transform as triplet (e.g. k,h,-l).
  --no-history    Do not add 'Reindexed with...' line to mtz HISTORY.
  --no-sort       Do not reorder reflections.
  --asu=ccp4|tnt  Write merged data in CCP4 (default) or TNT ASU.

Input file can be gzipped.
