fish-shell/doc_src/contains.txt

\section contains contains - test if a word is present in a list

\subsection contains-synopsis Synopsis
\fish{synopsis}
contains [OPTIONS] KEY [VALUES...]
\endfish

\subsection contains-description Description

`contains` tests whether the set `VALUES` contains the string `KEY`. If so, `contains` exits with status 0; if not, it exits with status 1.

The following options are available:

- `-i` or `--index` print the word index

Note that, like GNU tools and most of fish's builtins, `contains` interprets all arguments starting with a `-` as options to contains, until it reaches an argument that is `--` (two dashes). See the examples below.

\subsection contains-example Example

If $animals is a list of animals, the following will test if it contains a cat:

\fish
if contains cat $animals
   echo Your animal list is evil!
end
\endfish

This code will add some directories to $PATH if they aren't yet included:

\fish
for i in ~/bin /usr/local/bin
    if not contains $i $PATH
        set PATH $PATH $i
    end
end
\endfish

While this will check if `hasargs` was run with the `-q` option:

\fish
function hasargs
    if contains -- -q $argv
        echo '$argv contains a -q option'
    end
end
\endfish

The `--` here stops `contains` from treating `-q` to an option to itself. Instead it treats it as a normal string to check.