Appendix D
Regular Expressions

Most people are already familiar with the concept of using wildcards for filename expansion. Regular expressions serve a similar purpose, but have the potential of being much more sophisticated, complicated, and powerful.

It is beyond the scope or intent of this document to provide a full description of how to use regular expressions. A detailed discussion is often available in the UNIX man pages for ed, and the O'Reilly book UNIX in a Nutshell has a very nice chapter devoted to them. Razor's pattern matching technique is the same as that supported for ed. Since the filter panels of Razor do allow you to enter regular expressions, we offer here a quick table of some of the more familiar meta-characters.

Metacharacter	Special Meaning
.	Match any single character
^	Match following regular expression at beginning of line
$	Match preceding regular expression at end of line
*	Match zero or more instances of preceding expression
[]	Match any one of the characters enclosed between the brackets

To help complete the picture, we offer the following quick set of examples. They are by no means complete, but some of our new users have found this to be a good starting point.

Expression	Matches
out	Anything with the string `out', such as `about', `grout', and `snout'
^out	A string which starts with the three characters `out', such as `outside', but not `without'
^out$	Just the 3 character string `out'... nothing more, nothing less
^[Oo]ut	A string which starts with either `Out' or `out'
o.t	A string which has the letters `o' and `t' separated by a single character.
[AEO]l.*mo	Matches `Alamo', `Elmo', and `Old moss'
o[aeiou]t	A string which contains the letter `o', followed by any single vowel, followed by the letter `t'
out.*house	Any string which has `out' and `house' on the same line, in that same order. There can be zero or more letters between them
out*	The strings `ou', `out', `outt', `outtt', etc., etc.
^...$	A string with exactly 3 characters
^$	An empty field

(Part 1 of 1 for this section) (Generated 09/13/99 at 18:19:50)