What is non greedy match in regex?
A non-greedy match means that the regex engine matches as few characters as possible—so that it still can match the pattern in the given string. For example, the regex ‘a+?’ In other words, the non-greedy quantifiers give you the shortest possible match from a given position in the string.
Is sed greedy?
Yes, it’s greedy. In POSIX compliant system, not only sed but also all tools which use Basic Regular Expression, the matched pattern will always be greedy: The pattern a\{0,2\} matched any occurrence of character a between zero and two.
What in regex means?
A regular expression (sometimes called a rational expression) is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings, or string matching, i.e. “find and replace”-like operations. Regular expressions are a generalized way to match patterns with sequences of characters.
Is there non greedy matching in SED regexes?
No, sed regexes don’t have non-greedy matching. You can match all text up to the first occurrence of AC by using “anything not containing AC ” followed by AC, which does the same as Perl’s.*?AC.
Is there an equivalent of non-greedy in SED?
Sed has no equivalent of non-greedy. What we want to do is match
Is there a negation regex in portable SED?
And in portable sed, this isn’t possible at all, because the negation regex requires grouping an alternation which is present in extended regular expressions (e.g. in awk) but not in portable basic regular expressions. Some versions of sed, such as GNU sed, do have extensions to BRE that make it able to express all possible regular expressions.
How to use newline as a replacement character in SED?
With GNU sed, an approach is to use newline as the replacement character. Because sed processes one line at a time, newline never occurs in the pattern space, so one can do: