Portable Names (GNU tar 1.35)

#### 8.3.1 Portable Names

Use portable file and member names. A name is portable if it contains only ASCII letters and digits, ‘`/`’, ‘`.`’, ‘`_`’, and ‘`-`’; it cannot be empty, start with ‘`-`’ or ‘`//`’, or contain ‘`/-`’. Avoid deep directory nesting. For portability to old Unix hosts, limit your file name components to 14 characters or less.

If you intend to have your `tar` archives to be read on case-insensitive file systems like FAT32, you should not rely on case distinction for file names.