Differences between regular expression and wildcard pattern matching
In Perl regular expressions, the period (‘.’) character refers to any single character. It is similar to the question mark (‘?’) character in wildcard pattern matching. As a result:
• example.com not only matches example.com but also matches exampleacom, examplebcom, exampleccom and so on.
To match a special character such as the period ('.') and the asterisk (‘*’), regular expressions use the slash (‘\’) escape character. For example:
• To match example.com, the regular expression should be example\.com.
In Perl regular expressions, the asterisk (‘*’) means match 0 or more times of the character before it, not 0 or more times of any character. For example:
• exam*\.com matches exammmm.com but does not match eample.com.
To match any character 0 or more times, use ‘.*’ where ‘.’ means any character and the ‘*’ means 0 or more times. For example:
• the wildcard match pattern exam*.com is equivalent to the regular expression exam.*\.com.
See Also