Fedora Linux

Albert
a.out	backup
albert	_abc_
*x*	Any filename containing an x	xylophone.gif	constantinople
		nexus	ALEX
		old.x
*[09]	Any filename ending in a digit	file3	file
		menu.backup60	file3a
			file3.txt
			416-555-1212.phone
[Aa]???.txt	Any eight-character filename starting with a or A and ending in .txt	appl.txt	application.txt
		ax42.txt	a.txt
		Any1.txt	allow.txt
[azAZ][09]	Any two-character filename starting with a letter and ending with a digit	a9	No
		G7	7G
		N3	XX
			Fortran77
[!azAZ]*	Any filename that does not start with a letter	9lives.odt	abc.txt
[^azAZ]*		_whatever	Nevermore

4.3.1.4. Choosing easy-to-use filenames

Linux filenames can be up to 254 characters long and contain letters, spaces, digits, and most punctuation marks. However, names that contain certain punctuation marks or spaces cannot be used as command arguments unless you place quote marks around the name (and even then there may be problems). Linux filenames are also case-sensitive, so it's productive to adopt a consistent naming convention and stick to it.

Here are my recommendations for Linux filenames:

? Build the names from lowercase letters, digits, dots, hyphens, and underscores. Avoid all other