see https://github.com/porglezomp-misc/live-reloading-rs/issues/1#issuecomment-362738024

live-reloading-rs-watch.sh

#!/bin/bash
# see https://github.com/porglezomp-misc/live-reloading-rs/issues/1

set -e

name="libreloadable"
extension="dylib"
dir="./target/debug"
path="${dir}/${name}.${extension}"

cleanup() {
    rm -f "${dir}/${name}_"*;
}

trap cleanup EXIT

timestamp() {
    date +"%s";
}

run() {
    name2="${name}_$(timestamp)";

    for f in "$dir/$name".*; do cp -r "$f" "${f/$name/$name2}"; done
    for f in "$dir/deps/$name".*; do cp -r "$f" "${f/$name/$name2}"; done

    path2="${dir}/${name2}.${extension}";
    deps_path="${dir}/deps/${name2}.${extension}";

    install_name_tool -id "$deps_path" "$path2";
    install_name_tool -id "$deps_path" "$deps_path";
}

export name
export extension
export dir
export path
export -f timestamp
export -f run

fswatch -o "$path" | xargs -n1 sh -c '$(run);'