type "gradle" in bash and run the next-closest gradlew from current working directory, falling back to globally installed one.

.bashrc

function gradle() {
    local path=$(pwd)
    while 
        test ! -f $path/gradlew -a / != "$path" -a -n "$path"
    do 
        path=$(dirname $path)
    done
    if
        test -f $path/gradlew
    then 
        echo "Running $path/gradlew ..".
        $path/gradlew $@
    else 
        echo "No gradlew found in working dir and its parents!"
        # This is not recursive, because `which` (unlike `type`) doesn't find functions.
        local gradle_path=$(which gradle)
        test -f "$gradle_path" && $gradle_path $@
    fi
}

this tries ./gradlew
../gradlew
../../gradlew
and so on, stopping at /.