I am working with a huge genomics data file extending into very long rows. This is a *.dat System Default ISO-8859-1 encoding. I need to replace within specific section of the text only from a location (right in the middle of the text in each row) onwards –> to the end of each row and also vertically from start to end of the document). This is basically a square inside. When I use and click to highlight a section, the replace (Control + H) function moves across the entire text and does not constrain itself inside the section I need. Am I doing things wrong? Any ideas?