* |
Zero or more occurrences |
a* |
Zero or more a characters
(every string matches this expression) |
+ |
One or more occurrences |
a+ |
One or more a characters |
. |
Any single character except newline |
* |
Any number of any characters except for newline
characters (in other words, any string) |
\ |
Escape (turns off the special meaning associated
with a character) |
\. |
A period (.) character |
^ |
Beginning of line (if it is at the start of
the expression) |
^The.* |
Any line that starts with the string The |
$ |
End of line (if it is at the end of the expression) |
Monday\.$ |
Any line that ends with the string Monday followed
by a period (.) |
() |
Groupings |
(ref)+(bind)* |
At least one ref string then zero or more bind
strings |
[] |
character range (letters or digits) |
[sS]hall.*\.$ |
Any line that contains either shall or Shall,
and ends with a period (.) |
|
|
[^abc] |
Any character except a, b,
or c |
|
|
[a-zA-Z] |
Any alphabetic character (uppercase or lowercase) |
|
|
[0-9] |
Any numeric character (number between 0 and
9) |
| |
alternative |
(dat|doc) |
Either the string dat or
the string doc |