I have a large WIG files which are difficult to run in IGV, due to the size. I am only interested in chromosome M so I would like to extract signal from that chromosome and thus have a smaller file size. I found one solution on Stackoverflow (https://stackoverflow.com/questions/17354962/pcregrep-a-wiggle-file-to-extract-chromosome-multiple-line-regex-search), but that doesn't work at all. Any other ideas? I check UCSC utils and extensively searched online. I am also open to suggestions on bedgraph or similar formats.