In a regular expression, square brackets are used to indicate character classes, which matches any of the characters in the character set.| www.regular-expressions.info
In a regular expression, the asterisk or star causes the preceding token to be matched zero or more times, and the plus one or more times.| www.regular-expressions.info
The utility from the UNIX world, but now available on all platforms, including Windows, that first made regular expressions popular| www.regular-expressions.info
Understanding how a regex engine works internally enables you to craft better regular expressions by learning how to think like a regex engine.| www.regular-expressions.info
In a regular expression, the vertical bar or pipe symbol tells the regex engine to match any of two or more options| www.regular-expressions.info
Explains the two regex flavors defined in the POSIX standard: Basic Regular Expressions and Extended Regular Expressions| www.regular-expressions.info