def mdir(name=None):
    if name != None:
        lis = dir(name);
    else:
        lis = dir()
    lis.sort();
    lis = zip(lis[0::3],lis[1::3],lis[2::3])
    in_ = lambda x: [a.ljust(25) for a in x]
    out = lambda lis: ['\t'.join(in_(x)) for x in lis]
    print '\n'.join(out(lis))