Some fun with the ls command
ls # lists all files ls *.php # lists all php files ls t* # lists all files starting with t ls t*.php #lists all files starting with t and have a .php extension ls ? # lists all files having a one character filename ls tes? # lists all files starting with tes and having a 4 character filename ls [pqrs]* # lists all files starting with p, q, r or s ls [p-s]* # lists all files starting with p, q, r or s ls [!p-s]* # lists all files starting with any character other than p, q, r or s ls [^p-s]* # lists all files starting with any character other than p, q, r or s