Naming Files
Naming files and directories
- letters (uppercase and lowercase)
- digits
- the characters ``.'' (period) and ``_'' (underscore)
Using any other characters in the name of a file or directory may have side effects; a Unix command involving such a filename may be interpreted in a wacky way if the Unix shell (command interpreter) sees the special characters as part of the syntax of the command rather than merely part of a file name.
More information: file types/suffixes
