Linux “open files” FAQ: Can you share some examples of how to show open files on a Linux system — i.e., how to use the
Linux lsof command background
lsof command lists information about files that are open by processes running on the system. The
lsof command is an acronym for, “list of open files.” In this article I’ll share some
lsof command examples.
I assume you’re logged in as root
One other note: In these examples I'll assume that you're logged in as the Unix/Linux root user. If not, you’re
lsof command output may be significantly limited. If you’re logged in as a non-root user, either
su to root, or use
sudo to run these commands.
Basic Linux lsof command examples
lsof command by itself lists all open files belonging to all active processes on the system:
On my current macOS system, which has been running for a long time, this shows a lot of open files, 1,582 to be specific:
$ lsof | wc -l 1582
Note that I didn’t have to be logged in as the root user to see this information on my Mac system.
head command to
lsof shows what some of this output looks like:
$ lsof | head COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME loginwind 32 Al cwd DIR 14,2 1564 2 / loginwind 32 Al txt REG 14,2 1754096 243026930 /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow loginwind 32 Al txt REG 14,2 113744 3190067 /System/Library/LoginPlugins/FSDisconnect.loginPlugin/Contents/MacOS/FSDisconnect loginwind 32 Al txt REG 14,2 425504 117920371 /System/Library/LoginPlugins/DisplayServices.loginPlugin/Contents/MacOS/DisplayServices loginwind 32 Al txt REG 14,2 3144 3161654 /System/Library/ColorSync/Profiles/sRGB Profile.icc loginwind 32 Al txt REG 14,2 96704 242998403 /System/Library/PrivateFrameworks/MachineSettings.framework/Versions/A/MachineSettings loginwind 32 Al txt REG 14,2 51288 251253153 /private/var/folders/h5/h59HESVvEmG+3I4Q8lOAxE+++TI/-Caches-/mds/mdsDirectory.db loginwind 32 Al txt REG 14,2 724688 117923285 /System/Library/LoginPlugins/BezelServices.loginPlugin/Contents/MacOS/BezelServices loginwind 32 Al txt REG 14,2 329376 117923166 /System/Library/Extensions/IOHIDFamily.kext/Contents/PlugIns/IOHIDLib.plugin/Contents/MacOS/IOHIDLib
Common lsof options
As mentioned, these details go on for 1,582 lines, so it helps to have some way to weed through that output, whether that involves using the
grep command, or some of the
lsof options shown below.
This command lists all open files belonging to PID (process ID)
$ lsof -p 11925
This command lists all open files belonging to processes owned by the user named "al":
$ lsof -u al
This command lists files that are open in the directory specified, but it does not descend into sub-directories:
$ lsof +d '/Users/al'
The next command lists files that are open in the directory specified, and also descends into sub-directories. Beware: this can take a very long time to run for large directory structures:
$ lsof +D '/Users/al'
Summary: Linux lsof examples
I hope these Linux lsof command examples have been helpful. As you can see, the lsof command can be used to generate a list of open files on your Unix and Linux system with a variety of different command line options for different circumstances.
For more information on the lsof command, please see the "Related" block on this page, follow this link to lsof command search results on this website, or leave a note in the Comments section below.