Google spreadsheets scripting: search/replace hyperlinks

gistfile1.js

function MogensHyperlinkOffset() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  
  var ranges = ["M:M", "Q:Q"];
  
  var totalCells = 0;
  for (var r in ranges) { 
    ss.toast("Running range: "+ranges[r])
    var dRange = sheet.getRange(ranges[r])
    var numRows = dRange.getNumRows()
    var numCols = dRange.getNumColumns()
    
    ss.toast(numRows + " rows")
    Logger.log(numRows + " rows and "+numCols+" columns")
    for (var i = 1; i <= numRows; i++) {
      for (var j = 1; j <= numCols; j++) {
        cell = dRange.getCell(i, j)
        form = cell.getFormula()
        if (form != "") {
          mIndex = form.indexOf("Mogens")
          Logger.log({form: form, mIndex: mIndex});
          
          if (i % 20 == 0) {
            ss.toast("row: "+i);
          }
          
          if (mIndex > 20 && form.indexOf("HYPERLINK") > 0) {
            totalCells++;
            cell.setFormula('=HYPERLINK("file:///'+form.substr(mIndex))
          }
        }
      }
    }
    ss.toast("Range done: "+ranges[r])
  }
  
  ss.toast(totalCells, "Total number of cells edited", 300)
};

function hello() {
  Browser.msgBox("Hellooo!");
}