How to output only the overlapping region of two files? I have two files of genomic coordinates. I am trying to output only the overlapping region of fileA if it intersects with fileB. Not the original fileA coordinates.

fileA

chr1 25 50
chr1 75 200


fileB

chr1 10 60
chr1 80 90


desired output

chr1 25 50
chr1 80 90
bedtools is my go-to program for operations on genomic intervals. In particular, the bedtools intersect operation is what you're looking for here.

$ cat fileA
chr1    25      50
chr1    75      200
$ cat fileB
chr1    10      60
chr1    80      90
$ bedtools intersect -a fileA -b fileB                                                           
chr1    25      50
chr1    80      90


Make sure that the values are separated by tabs rather than spaces, or bedtools will have trouble reading the files.