plain cat (no options) uses max(128 * 1024, st_blksize) aligned to page_size for reads and writes. so you get the best block size for reads and writes. I can't

plain cat (no options) uses max(128 * 1024, st_blksize) aligned to page_size for reads and writes. so you get the best block size for reads and writes. I can't speak to what the shell does, though.