why is the output of `du` often so different from `du -b`

Question

why is the output of du often so different from du -b? -b is shorthand for --apparent-size --block-size=1. only using

Answer 1

Files and folders have their real size and the size on disk

• --apparent-size is file or folder real size

• size on disk is the amount of bytes the file or folder takes on disk. Same thing when using just du

If you encounter that apparent-size is almost always several magnitudes higher than disk usage then it means that you have a lot of (`sparse') files of files with internal fragmentation or indirect blocks.