checkIntegrity <- function(x, opts = NULL, ...) {
  
  ## if options have not been passed down, create them from '...'
  if (is.null(opts))
    opts <- combineOptions(...)
  
  opts$stubbornness <- stubborn(opts$stubbornness)
  
  iw   <- getOption("warn") 
  options(warn=-1)
  on.exit(options(warn=iw))
  
  if(!opts$gdalOk)
  {
    warning("Something wrong with your GDAL installation, see '?MODISoptions' for more details")
  } else
  {
    cmd <- paste0(opts$gdalPath,"gdalinfo ") 
    out <- rep(NA,length(x))
    
    for (i in seq_along(x))
    {
      if (basename(x[i])=="NA" | is.na(basename(x[i])))
      {
        out[i] <- NA
      } else
      {
        if (dirname(x[i])==".")
        {
          x[i] <- paste0(genString(x=x[i],remote=FALSE,...)$localPath, basename(x[i]))        
        }
        
        if (!file.exists(x[i]))
        {
          out[i] <- NA
        } else
        {
          try(a <- system(paste0(cmd,correctPath(x[i],isFile=TRUE)), intern=TRUE), silent=TRUE)
          
          if(length(grep(a,pattern="gdalinfo failed")==1) | length(a)==0)
          {
            out[i] <- FALSE
          } else 
          {
            out[i] <- TRUE
          }
        }
      }
    }
    return(out)
  }
}