What it does:

The input data file is sorted and compressed by bgzip which has a gzip(1) like interface. Tabix requires the file to be compressed using this tool first.

Citation:

Tabix was written by Heng Li. The BGZF library was originally implemented by Bob Handsaker and modified by Heng Li for remote file access and in-memory caching.

http://samtools.sourceforge.net/tabix.shtml

Example:

(grep ^"#" in.gff; grep -v ^"#" in.gff | sort -k1,1 -k4,4n) | bgzip > sorted.gff.gz;

tabix -p gff sorted.gff.gz;

tabix sorted.gff.gz chr1:10,000,000-20,000,000;