Syntax
- POSIX style, end of word:
[[:>:]] - POSIX style, start of word:
[[:<:]] - POSIX style, word boundary:
[[:<:][:>:]] - SVR4/GNU, end of word:
\> - SVR4/GNU, start of word:
\< - Perl/GNU, word boundary:
\b - Tcl, end of word:
\M - Tcl, start of word:
\m - Tcl, word boundary:
\y - Portable ERE, start of word:
(^|[^[:alnum:]_]) - Portable ERE, end of word:
([^[:alnum:]_]|$)
