fish-shell/share/functions/realpath.fish

# Provide a minimalist realpath implementation to help deal with platforms that may not provide it
# as a command. If a realpath command is available simply pass all arguments thru to it. If not
# fallback to alternative solutions.

# The following is slightly subtle. The first time `realpath` is invoked by autoloading this script
# will be read. If we see that there is an external realpath command we just return. That will cause
# fish to run the external command. Or, if there is a grealpath, we alias it.
# On the other hand, if an external command isn't found we provide a function that will facilitate
# fallback behavion through our builtin.

if not command -s realpath >/dev/null
    # If there is a HomeBrew installed version of GNU realpath named grealpath use that.
    if command -s grealpath >/dev/null
        function realpath -w grealpath -d "print the resolved path [grealpath]"
            grealpath $argv
        end
        exit 0
    end

    function realpath -d "return an absolute path without symlinks"
        if test -z "$argv"
            printf "usage: %s%s%s %sfile%s …\n" (set_color -o) $_ (set_color normal) (set_color -u) (set_color normal)
            echo "       resolves files as absolute paths without symlinks"
            return 1
        end

        # Loop over arguments - allow our realpath to work on more than one path per invocation
        # like gnu/bsd realpath.
        for arg in $argv
            switch $arg
                # These - no can do our realpath
                case -s --strip --no-symlinks -z --zero --relative-base\* --relative-to\*
                    __fish_print_help realpath
                    return 2

                case -h --help --version
                    __fish_print_help realpath
                    return 0

                # Handle commands called with these arguments by dropping the arguments to protect
                # realpath from them. There are no sure things here.
                case -e --canonicalize-existing --physical -P -q --quiet -m --canonicalize-missing
                    continue

                case "*"
                    builtin realpath $arg
            end
        end
    end
end