File Naming Conventions

• upper and lower case letters, can be mixed

• digits

• underscore, dash, and period (aka dot or full stop)

• up to 255 chars on modern versions

• case sensitive: demo.pdf, Demo.pdf, and demo.PDF are not the same file

• a filename starting with a period (".") designates a special file (sometimes called a "hidden file"); use the -a option of ls to list

• The filename "." alone designates the current directory, whatever that happens to be ...

• While ".." designates the parent of the current directory