I usually use `bedtools intersect` to find overlapping regions of bed files, but it seems like this tool can only output overlap between a pair of files. I need something that can do the following from many bed files and **only** report regions contained in all of the bed files.

Example input from 4 separate bed files:  

```
chr1    50    100
chr1    60    120
chr1    30    90
chr1    50    90
```

Desired output:

```
chr1    60    90
```

Any tools for this? Maybe I should just  `cat` all the bed files together and merge them?
https://www.biostars.org/p/172566/ (`bedops` option)<br>
<br>

There is also

     bedtools multiinter
    
    Tool:    bedtools multiinter (aka multiIntersectBed)
    Version: v2.26.0
    Summary: Identifies common intervals among multiple
             BED/GFF/VCF files.
    
    Usage:   bedtools multiinter [OPTIONS] -i FILE1 FILE2 .. FILEn
             Requires that each interval file is sorted by chrom/start. 

