KN’s Reviews > Mastering Regular Expressions > Status Update

g/RegularExpression/p -> Global Regular Expression Print -> grep
Stephen Kleen, Ken Thompson, Alfred Aho

POSIX standard - BREs vs EREs

The birth of Perl -> Perl Compatible RE

s/(?=\bJeff)(?=s\b)/‘/g

Match position (~empty substring) -> replace with ‘ -> effectively insert missing ‘

Non-consuming matches
Lookahead: ?=
Lookbehind: ?<=