Regular expression reference charactersRegular expression anchor characters
Anchor characters indicate that the following or preceding characters must be next to a special position in a string. The characters next to anchor characters are included in a match, not the anchor characters themselves. For example, in the string "The big cat and the small cat", the regular expression /cat$/ will match the "cat" at the end of the string, and the match will include only the three characters "cat". The "$" is an anchor character indicating the end of a string (or line if a multiline search is being done).
The following table lists the anchor characters, metacharacters, and their meanings.
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Character
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Anchor meaning
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^
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The beginning of a string (or line if doing a multiline search). (See \A below.)
Example: /^The/
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$
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The end of a string (or line if doing a multiline search). (See \Z below.)
Example: /cat$/
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\A
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Matches the beginning of a string only. (See $ above.)
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\b
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A word boundary. Match any character that is not considered to be a valid character for a word in programming. The character class "\W", not a word character, is similar. There are two differences. One, "\b" also matches a backspace. Two, "\W" is included in a match, since it is regular expression character, but "\b" is not included in a match.
Example: /\bthe\b/
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\B
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Not a word boundary. The character class "\w" is similar. The most notable difference is that "\w" is included in a match, and "\B" is not.
Example: /l\B/
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\Z
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Matches the end of a string only. (See ^ above.)
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Regular expression reference characters