Good file names: use characters: upper,lower case letters, 
digits, underscore, period, comma, and plus sign.

1st character = . implies a hidden file

System V Rel 3 or before uses a maximum of 14 character file names [Rare-RK]
System V Rel 4 or BSD versions use a maximum of 256 character file names [Most Implementations now RK]

File name expansion (a facility performed by the shell)
                               For a filename:
= Wildcards in DOS: ?	In the current directory match any character
		    *	In the current directory match zero or more characters
	      [aeiou]	In the current directory, match a vowel in a single
				character position
	        [a-f]   In the current directory, match the first 6 letters of
				the alphabet in a single character position
	       [!A-Z]   In the current directory, match anything except a 
				capital letter in a single character position.

Note: matching a hidden file requires the leading . to be specified: .* not *
Forward slashes will not be matched by * or ?. Use them explicitly also.

Examples:

$ # What do these commands with wild cards match?
$ # What error message do you get with ls or echo if there is no match?
$ echo *a
$ ls *[xyz]
$ echo *.?
$ ls ??
$ echo *.obj

$ ls m*
$ ls -l /usr/a[acs-y]*
$ echo *add*
$ mv Chap?.unix archive
$ cat *.year > manyyears
$ cat chap[1-6] > manychapts

$ cp accounts89 accounts.arc
$ cp account6 payments $HOME/archives
$ cp account* archives

$ mv accounts89 accounts.arc
$ mv payments $HOME/archive/payments.89
$ mv account6 payments $HOME/archives
$ mv acc*89 archives

Questions? Robert Katz: rkatz@ned.highline.edu
Last Update June 26, 2003