type inputfile {};
type outputfile {};
  
(outputfile o) sortFiles(inputfile file) {
    app {
        sort "-n" @filename(file) stdout=@filename(o);
    }
}

(outputfile ofiles[]) main(inputfile files[]) {
    foreach file,i in files {
        ofiles[i]=sortFiles(file);
    }
}

inputfile files[]<filesys_mapper;location="./data",prefix="sdata">;
outputfile ofiles[]<simple_mapper;prefix="out",suffix=".txt">; 

ofiles=main(files);