Google Message Security for Google Apps Administration Guide - Manual (Page 226)

226 Message Security for Google Apps Administration Guide
Match Whole Word Only
Note: You can also use the rule filter “matches any word in” to create a rule that
matches a specific word. Include the word you want to match in the rule value.
Match Exact Phrase Only
Usage example Match the word hell. Don’t match the word hello, shell,
shellac, and so on.
Regex example (\W|^)hell(\W|$)
Note • \W matches any character that’s not a letter, digit, or
underscore. It prevents the regex from matching letters
before or after the word.
Important: When creating a regex to match whole words,
ensure that you include the \W character class, to help to
avoid capturing legitimate messages.
• ^ matches the start of a new line. Allows the regex to
match the word if it appears at the beginning of a line,
with no characters before it.
• $ matches the end of a line. Allows the regex to match
the word if it appears at the the end of a line, with no
characters after it.
Usage example Match the phrase stock tips.
Regex
examples 1: ( \W|^)stock\stips(\W|$)
2: (\W|^)stock\s{0,3}tips(\W|$)
3: (\W|^)stock\s{0,3}tip(s){0,1}(\W|$)