8 Basic lsof Commands Every Sysadmin Needs to Know

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by Super User, 3 years ago
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lsof basics - list open files on Linux and Unix (expand for timestamps and details).

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About this Video:

In this video I introduce the 'lsof' command, found on Linux and Unix systems. I'll show you some practical examples and teach you how to explore what's happening with the filesytem in a system or process.

1:00 Which files are open?
lsof

2:56 Which processes have this file open?
lsof /var/log/nginx-error.log

4:49 Which files does process X have open?
lsof -p 1
lsof -p `pgrep ABC`

7:08 Where is the binary for this process?
lsof -p ABC | grep bin

7:44 Which shared libraries is this program using? (manually upgrading software, i.e. openssl)
lsof -p PID | grep .so

8:03 Where is this thing logging to?
lsof -p ABC | grep log

8:40 Which processes still have this old library open?
lsof grep libname.so

9:45 Which files does user XYZ have open?
lsof -u XYZ
lsof -u XYZ -i # network only

10:25 Which process is listening on Port X (or using Protocol Y)?
lsof -i :80
lsof -i tcp

11:21 Super lsof Story Time!

14:03 Exercises