Metacharacter Description Example
. Any single character, including white
space
'..ain' matches sequences of five
consecutive characters that end with
'ain'.[c 1 c 2 c 3 ] Any character contained within the
square brackets. The following
characters are treated literally: $
|. * +? and - when not used to
indicate a range.
'[rp.]ain' matches 'rain' or 'pain'
or '.ain'.[^c 1 c 2 c 3 ] Any character not contained within
the square brackets. The following
characters are treated literally: $
|. * +? and - when not used to
indicate a range.
'[^*rp]ain' matches all four-letter
sequences that end in 'ain', except
'rain' and 'pain' and '*ain'. For
example, it matches 'gain', 'lain', or
'vain'.[c 1 -c 2 ] Any character in the range of c 1
through c 2
'[A-G]' matches a single character in
the range of A through G.\w Any alphabetic, numeric, or
underscore character. For English
character sets, \w is equivalent to
[a-zA-Z_0-9]
'\w*' identifies a word.\W Any character that is not alphabetic,
numeric, or underscore. For English
character sets, \W is equivalent to
[^a-zA-Z_0-9]
'\W*' identifies a term that is not a
word.\s Any white-space character;
equivalent to [ \f\n\r\t\v]
'\w*n\s' matches words that end with
the letter n, followed by a white-space
character.\S Any non-white-space character;
equivalent to [^ \f\n\r\t\v]
'\d\S' matches a numeric digit followed
by any non-white-space character.\d Any numeric digit; equivalent to
[0-9]
'\d*' matches any number of
consecutive digits.\D Any nondigit character; equivalent to
[^0-9]
'\w*\D\>' matches words that do not
end with a numeric digit.\oN or \o{N} Character of octal value N '\o{40}' matches the space character,
defined by octal 40.
Regular Expressions