Character

Matches

^ (at the beginning only)

beginning of line

.

any single character

[abc]

any single character that belongs to the set abc

[^abc]

any single character that does not belong to the set abc

*

zero or more occurrences of the preceding character

+

one or more occurrences of the preceding character

\t

a tab character

\s

a space character

\w

white space (a tab or a space character)

$

the end of the line

Set type

Meaning

[<character list>]
eg. [abcde]

Matches any character within the set. The set can be any number of characters long.

[x-y]
eg. [a-z]

Matches on any character within the range of x through y, inclusively. The ASCII value of x must be less than that of y.

combination;
eg. [WXYa-z0-9]

Character lists and ranges may be combined.