BMRB and the NMR community have developed and made available a collection of software code for manipulating NMR data files, data and developing NMR experiments. The code is provided "as is" and is without warranty of any kind.
A collection of software for manipulating NMR-STAR data files:
PyNMRSTAR is an object-oriented Python interface to NMR-STAR files. It makes reading from, modifying, validating, and comparing NMR-STAR files easy. Documentation is provided on the GitHub page.
The following tools are no longer actively maintained:
pystarlib is another Python interface to NMR-STAR and mmCIF files.