tldr-实用的命令查询工具

介绍主页（上面有多种安装该工具的方法）：https://github.com/tldr-pages/tldr
这里只演示使用pip的安装方法，

pip install tldr

查询lsof命令的使用方法：

Mac-Pro:~ K$ tldr lsof
# lsof

  Lists open files and the corresponding processes.
  Note: Root privileges (or sudo) is required to list files opened by others.

- Find the processes that have a given file open:

  lsof path/to/file

- Find the process that opened a local internet port:

  lsof -i :port

- Only output the process ID (PID):

  lsof -t path/to/file

- List files opened by the given user:

  lsof -u username

- List files opened by the given command or process:

  lsof -c process_or_command_name

- List files opened by a specific process, given its PID:

  lsof -p PID

- List open files in a directory:

  lsof +D path/to/directory

总体来说比起man命令查询的结果要简洁多，每个使用方法都有解释。