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Appendix F Summary of all Regular Expressions

Regular expressions are based on POSIX EREs (Extended Regular Expressions). Regexps are composed of characters. Here is a short-list of them all:

c
matches the character c (assuming c is none of the characters listed below).
\c
matches the literal character c.
.
matches any character.
^
matches the beginning of a string.
$
matches the end of a string.
[abc...]
matches any of the characters abc... (character list).
[[:keyword:]]
matches any character in the character class keyword. Allowable classes are alnum, alpha, blank, cntrl, digit, graph, lower, print, punct, space, upper, and xdigit.
[[.element.]]
matches the multi-character collating element. Gcal does not currently support collating symbols.
[[=list=]]
matches any of the equivalent characters in list. Gcal does not currently support equivalence classes.
[^abc...]
matches any character except abc... (negated resp. complemented character list).
r1|r2
matches either r1 or r2 (alternation).
r1r2
matches r1, and then r2 (concatenation).
r+
matches one or more r's.
r*
matches zero or more r's.
r?
matches zero or one r's.
(r)
matches r (grouping).
r{n}
r{n,}
r{n,m}
matches at least n, n to any number, or n to m occurrences of r (interval expressions).
\b
matches the empty string at either the beginning or the end of a word.
\B
matches the empty string within a word.
\<
matches the empty string at the beginning of a word.
\>
matches the empty string at the end of a word.
\w
matches any word-constituent character (alphanumeric characters and the underscore).
\W
matches any character that is not word-constituent.
\`
matches the empty string at the beginning of a buffer1.
\'
matches the empty string at the end of a buffer.

Footnotes

[1] The same as a text part of a resource file line in Gcal.