Regex Basics

In order to match complete non-empty lines which do NOT contain a specific string, let's say, the word TEXT, with that exact case, here are, below, 5 regexes.

Performs a comparison to determine whether a string matches or does not match a specified pattern. Both inputs must be text expressions. String functions (regular... · Regexp_replace · Regexp_substr · Regexp_count

A regular expression is a pattern that the regular expression engine attempts to match in input text. A pattern consists of one or more character literals, ... Character Classes · NET Regular Expressions · Character Escapes · Options

You can do this using a negative lookahead assertion. The PCRE regular expression below will match any line that does not contain the word “word”.

I'm looking for a general regex construct to match everything in pattern x EXCEPT matches to pattern y. This is hard to explain both completely and concisely.

No, there's no direct not operator. At least not the way you hope for. You can use a zero-width negative lookahead, however.

I'd like to select a lines with does not contain a word SCREEN. I tried the following regex (?<!SCREEN).+ but it seems not to work - selects all ...

I am trying to write a regex pattern to pick the string that contains the word best and also not contain mew.

Your question is not very clear, but you may want the invert match option, grep –v, which means select lines which do not match the regex.

The regex not operator, also known as the negation operator, is a useful tool in programming for pattern matching and string manipulation. The Basics of Regular... · Using the Negation Operator · Examples in Different...