A cheat sheet about regular expressions used in Sublime Text.

Special characters

expressionDescription
.Match any character
^Match line begin
$Match line end
*Match previous RE 0 or more times greedily
*?Match previous RE 0 or more times non-greedily
+Match previous RE 1 or more times greedily
+?Match previous RE 1 or more times non-greedily
?Match previous RE 0 or 1 time greedily
??Match previous RE 0 or 1 time non-greedily
A|BMatch either RE A or B
{m}Match previous RE exactly m times
{m,n}Match previous RE m to n times greedily
{m, n}?Match previous RE m to n times, non-greedily

Character set

expressionDescription
[abc]Match either a, b or c
[^abc]Match any character not in this set (i.e., not a, b and c)
[a-z]Match the range from a to z
[a-f2-8]Match the range from a to f or the range from 2 to 8
[a\-z]Match a, - or z
[a-]Match a, -
[-a]Match -, a
[{}*|()[]+\^$.?]Match either one of the chacters in []{}*|()+^$?.
  • Note that you can also use character class inside [], for example, [\w] matches any character in word character class.

Character class

“Multiple character” character class

An expression of the form [[:name:]] matches the named character class name.

class nameDescription
alnumAny alpha-numeric character
alphaAny alphabetic character.
digitAny decimal digit.
xdigitAny hexadecimal digit character.
lowerAny lower case character.
upperAny upper case character.
cntrlAny control character1.
printAny printable character.
punctAny punctuation character. 2
spaceAny whitespace character. 3
wordAny word character (alphanumeric characters plus the underscore).

Note: To use upper and lower, you have to enable case sensitve search.

“Single character” character class

class nameDescription
\dEqual to [[:digit:]]
\lEqual to [[:lower:]]
\uEqual to [[:upper:]]
\sEqual to [[:space:]]
\wEqual to [[:word:]]
\DEqual to [^[:digit:]]
\LEqual to [^[:lower:]]
\UEqual to [^[:upper:]]
\WEqual to [^[:word:]]

Regex groups

Defining capture groups

expressionDescription
(?<NAME>pattern)Define a regex group named NAME which you can later refer to with \g{NAME}
(?=pattern)Positive lookahead, consumes zero characters, the preceding RE only matches if this matches
(?!pattern)Negative lookahead, consumes zero characters, the preceding RE only matches if this does not match
(?<=pattern)Positive lookbehind, consumes zero characters, the following RE will only match if preceded with this fixed length RE.
(?<!pattern)Negative lookbehind, consumes zero characters, the following RE will only match if not preceded with this fixed length RE.

Refering to matching groups (capture groups)

expressionDescription
\1Refer to first regex group
\g{1}Refer to first regex group
\g{12}Refer to 12th regex group
\g{-1}Refer to last regex group
\g{-2}Refer to last but one regex group
  • The regex groups are indexed by the order of their opening braces.
  • Note the \g{NUM} form allows for matching regex group index larger than 9, for example, \g{12}.

Miscellaneous

Escapes

class nameDescription
\xddA hexadecimal escape sequence - matches the single character whose code point is 0xdd.
\x{dddd}A hexadecimal escape sequence - matches the single character whose code point is 0xdddd.

Word boundaries

The following escape sequences match the boundaries of words:

class nameDescription
\<Matches the start of a word.
\>Matches the end of a word.
\bMatches a word boundary (the start or end of a word).
\BMatches only when not at a word boundary.

References

The title image is taken from here.

  1. Control character explanation: https://en.wikipedia.org/wiki/Control_character ↩︎

  2. There are 14 punctuation marks in English: https://grammar.yourdictionary.com/punctuation/what/fourteen-punctuation-marks.html ↩︎

  3. For whitespace characters, see https://en.wikipedia.org/wiki/Whitespace_character ↩︎