intersect">intersectsubtract">subtractmerge">mergeflank">flankgenomecov">genomecov https://bedtools.readthedocs.io/en/latest/ intersect 取交集 subtract 取反 _ merge 合并overlap的区间 _ flank 两侧扩充 _ unionbedg 合并多个bed文件 genomecov 覆盖度统计 _