Multi-character RS,FS,PS

You can process CRLF-terminated DKVP files with mlr --dkvp --rs crlf.
You can process LF-terminated CSV files with mlr --csv --rs lf.
You can process TSV using mlr --fs tab; you can convert TSV to CSV using mlr --ifs tab --ofs comma.
Along with many more possibilities.
Please see mlr -h for more information.

There is one minor, backward-incompatible change which I felt not worth calling this 3.0.0: default field separator for NIDX format is now space, not comma.