Run a command whenever changes are detected by inotify

iwatch

#!/bin/bash
set -euo pipefail
declare -a ARGS=() INOTIFY_ARGS
while (($#)); do
    case $1 in
        --) break;;
        *) ARGS+=("$1");;
    esac
    shift
done
if [[ ${1:-} = -- ]]; then
    shift
    INOTIFY_ARGS=("${ARGS[@]}") ARGS=("$@")
else
    INOTIFY_ARGS=(-r .)
fi
if ! ((${#ARGS[*]})); then
    echo "usage: $(basename "$0") [inotifywait args] [--] <command> [args]"
    exit
fi
run() {
    if command "${ARGS[@]}"; then
        echo ok.
    else
        echo "fail. $?"
    fi
}
exec {fd}< <(
    command inotifywait -e modify -e attrib -e move -e create -e delete -m "${INOTIFY_ARGS[@]}"
); pid=$!
trap "kill $pid" EXIT
trap exit SIGINT SIGQUIT SIGTERM
run $fd<&-
while read -r -u $fd; do
    printf ':: %s\n' "$REPLY" >&2
    while read -r -t 1 -u $fd; do
        printf ':: %s\n' "$REPLY" >&2
    done
    run $fd<&-
done