Linux lsof

lsof（list open files）是一个列出当前系统打开文件的工具。在linux环境下，任何事物都以文件的形式存在，通过文件不仅仅可以访问常规数据，还可以访问网络连接和硬件。所以如传输控制协议 (TCP) 和用户数据报协议 (UDP) 套接字等，系统在后台都为该应用程序分配了一个文件描述符，无论这个文件的本质如何，该文件描述符为应用程序与基础操作系统之间的交互提供了通用接口。因为应用程序打开文件的描述符列表提供了大量关于这个应用程序本身的信息，因此通过lsof工具能够查看这个列表对系统监测以及排错将是很有帮助的。

lsof meaning ‘LiSt Open Files’ is used to find out which files are open by which process. As we all know Linux/Unix considers everything as a files (pipes, sockets, directories, devices etc). One of the reason to use lsof command is when a disk cannot be unmounted as it says the files are being used. With the help of this command we can easily identify the files which are in use.

1. Find Processes running on Specific Port :
   lsof -i TCP:22
   sudo lsof -i -P | grep -i LISTEN

2. Search by PID :
   lsof -p 1 (The below example only shows whose PID is 1 [One].)

3. ff

Related Blogs

1. 15 Linux lsof Command Examples (Identify Open Files)