我正在尝试将简单的 rsync 同步到 USB 硬盘，命令是
rsync -az --modify-window=2 /home /mnt/exthd/tmp/
我以 root 身份运行它。
但我收到很多错误，似乎都与权限不足有关：
rsync: chown "/mnt/exthd/tmp/home/someuser" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/someuser/.bash_logout" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/someuser/.bash_profile" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/someuser/.bashrc" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/guest" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/guest/.bash_logout" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/guest/.bash_profile" failed: Operation not permitted (1)
rsync: chown "/mnt/exthd/tmp/home/guest/.bashrc" failed: Operation not permitted (1)
rsync: symlink …rsync ×1