Negate if condition in bash script
You can choose: if [[ $? -ne 0 ]]; then # -ne: not equal if ! [[ $? -eq 0 ]]; then # -eq: equal if [[ ! $? -eq 0 ]]; then ! inverts the return of the following expression, respectively.
negate
How can I negate the return-value of a process?
Previously, the answer was presented with what’s now the first section as the last section. POSIX Shell includes a ! operator Poking around the shell specification for other issues, I recently (September 2015) noticed that the POSIX shell supports a ! operator. For example, it is listed as a reserved word and can appear at … Read more
Negating a backreference in Regular Expressions
Instead of a negated character class, you have to use a negative lookahead: \bvalue\s*=\s*([“‘])(?:(?!\1).)*\1 (?:(?!\1).)* consumes one character at a time, after the lookahead has confirmed that the character is not whatever was matched by the capturing group, ([“”]). A character class, negated or not, can only match one character at a time. As far … Read more
How to negate a method reference predicate
Predicate.not( … ) java-11 offers a new method Predicate#not So you can negate the method reference: Stream<String> s = …; long nonEmptyStrings = s.filter(Predicate.not(String::isEmpty)).count();