Regular Expression

Regular Expressions

• POSIX Basic Regular Expression

  • grep

• POSIX Extended Regular Expression

  • egrep
  • awk
  • emacs

GNU Extensions

Shorthand Classes

shorthand	equivalence
\w	[[:alnum:]_]
\W	[^[:alnum:]_]
\s	[[:space:]]
\S	[^[:space:]]

Word Boundaries

shorthand	matches
\b	position at a word boundary
\B	position not at a word boundary
\<	position at the start of a word
\>	position at the end of a word
\` (backtick)	position at the start of subject string
\' (single quote)	position at the end of subject string