LiveFire Labs: Online UNIX Training with Hands-on Internet Lab


"Taking a LiveFire Labs' course is an excellent way to learn Linux/Unix. The lessons are well thought out, the material is explained thoroughly, and you get to perform exercises on a real Linux/Unix box. It was money well spent."

Ray S.
Pembrook Pines, Florida



LiveFire Labs' UNIX and Linux Operating System Fundamentals course was very enjoyable. Although I regularly used UNIX systems for 16 years, I haven't done so since 2000. This course was a great refresher. The exercises were fun and helped me gain a real feel for working with UNIX/Linux OS. Thanks very much!"

Ming Sabourin
Senior Technical Writer
Nuance Communications, Inc.
Montréal, Canada

Read more student testimonials...


Receive UNIX Tips, Tricks, and Shell Scripts by Email







LiveFire Labs' UNIX Tip, Trick, or Shell Script of the Week

UNIX Special Characters (Metacharacters) - Asterisk, Question Mark, Brackets, and Hyphen

Special Characters (Metacharacters)

Special characters, or metacharacters, have a special meaning to the shell. They can be used as wildcards to specify the name of a file without having to type out the file's full name. Some of the most commonly used metacharacters are "*", "?", "[]", and "-".


The Asterisk

The * (asterisk) metacharacter is used to match any and all characters. Typing the following command will list all files in the working directory that begin with the letter l regardless of what characters come after it:

$ ls l*

The * (asterisk) metacharacter can be used anywhere in the filename. It does not necessarily have to be the last character.


The Question Mark

The ? (question mark) metacharacter is used to match a single character in a filename. Typing the following will list all of the files that start with "livefirelabs" and end with a single character:

$ ls livefirelabs?

Like the asterisk, the ? (question mark) metacharacter can be used as a substitution for any character in the filename.




Brackets

Brackets ([…]) are used to match a set of specified characters. A comma separates each character within the set. Typing the following will list all files beginning with "a", "b", or "c":

$ ls [a,b,c]*

The Hyphen

Using the - (hyphen) metacharacter within [] (brackets) is used to match a specified range of characters. Typing the following will list all files beginning with a lowercase letter of the alphabet:

$ ls [a-z]*

If there are directory names meeting the specified range, their name and contents will also be displayed.

TIP: Although possible, it is highly recommended that you do not create file names containing metacharacters.