Fish 3.3.1 shell: how do I negate the results of a string match?

Question

as above.

basically I want to implement something like

if not match then
  do these things
else
  do these other things
fi

Thanks

Answer 1

It depends on what you mean by match, but if you mean "exactly match", you can use the string match builtin with a plain argument.

if not string match --quiet -- "some_string" $some_argument
    echo no match
else
    echo match
end

To match within a string, you can use a glob in some_string, or a regular expression with string match --regex.

Answer 2

As an alternative to not string match -q -- $pattern $string (as mentioned by @Zanchey), you can also do:

if string match -vq -- $pattern $string
  echo no match
else
  echo match
end

(-v like in grep, or --invert (like GNU grep's --invert-match) to invert the match).

You'll see a difference when matching the pattern against more than one string (like when $string above is a list with more than one element) or when matching against no string at all ($string is an empty list).

if not string match -q -- $pattern $string1 $string2
  echo none of the strings matched
else
  echo at least one the strings matched
end

if string match -vq -- $pattern $string1 $string2
  echo at least one of the strings did not match
else
  echo all the strings matched
end