Anchors

Code

^abc      starts with abc
abc$      ends with abc
^abc$     exactly abc
\bword\b  word boundary
\B        non-word boundary
\A        start of string (PCRE)
\z        end of string (PCRE)
\Z        end of string (before final newline)

Explanation

Anchors are zero-width assertions that match a position rather than a character. ^ and $ match the start and end of a line, but with the multiline flag they match at every line boundary. \b matches between a word and a non-word character, while \A and \z always refer to the whole string start and end in PCRE-style engines.

More Regex Snippets