List Open Files


If you try to unmount a partition and get a message like this:

# umount /media/usbdisk/
umount: /media/usbdisk: device is busy

use the lsof command to find out what programs are using what files:

# lsof /media/usbdisk/
bash    6925 root cwd  DIR   8,17 4096    1 /media/usbdisk/
xmms    6979 root cwd  DIR   8,17 4096    1 /media/usbdisk/

This shows that the programs bash and xmms are using the device. For an even clearer picture, use the device name rather than the mountpoint:

# lsof /dev/sdb1
bash    6925 root cwd  DIR   8,17    4096    1 /media/usbdisk
xmms    6979 root cwd  DIR   8,17    4096    1 /media/usbdisk
xmms    6979 root  8r  REG   8,17 2713101  377 /media/usbdisk/a.mp3

You either can wait until those processes exit or terminate them manually.


Jagadish Kavuturu


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

That's crazy! but what the hey, sometimes we're lazy :)

maskedfrog's picture

Thanx for the tip Anthony,
THAT will come in handy. The times I've waited for a cd to umount
and waited...and waited...and gave up and rebooted :-(
More apt to use in the examples shown though, waiting for a process to finish and don't want to forget to umount so just do it the "lazy" way.
Uptimes should shoot thru the roof now :-))


Hatta's picture

In my experience 'lsof' is extremely slow. So slow that I can log off and log back on before I'd expect lsof to finish. Are there any tricks to speed it up to the point that it's usable?

lsof is NOT slow at all.

VIKAS's picture

lsof is NOT slow at all.
I believe there would be other problems with your machine.

A very powerful command

SteveC's picture

The lsof command is far more powerful than the article implies. It's worth spending some time reading the documentation. My most common use is to locate connections with the -i option:

# all tcp connections
lsof -i tcp

# connections to mail server on
lsof -i

# What's connected to my PostgreSQL server via TCP/IP?
lsof -i :5432

# What is my browser connected to?
lsof -i :80

Killing with fuser

Anonymous's picture

    lsof +D [device]
shows nothing

you can use
    fuser -m [device]
to show processes that say that are using the device.

and you can use
    fuser -km [device]
to directly kill them all

Doesn't always work

Ivan V's picture

Unfortunately, many times, neither lsof nor fuser have worked for me (the device says busy but nothing comes up)...

The only solution in those cases is for me to logoff or try to find a possible culprit.

Thanks! That's a cool trick!

Durand's picture

Thanks! That's a cool trick!

Thanks, a much needed tip.

Anonymous's picture

Thanks, a much needed tip.

Nice tip

vinit's picture

Thanks for the gr8 tip.

Short and to the point

Anonymous's picture

Short and to the point Howto. Nice.

Don't forget fuser!

Devin's picture

You can also use fuser if you know which directory or file is open and you want to find the offending process.

fuser [file]

You can also use the "lazy

Anthony Lawrence's picture

You can also use the "lazy umount" - see for examples.

One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems

As Linux continues to play an ever increasing role in corporate data centers and institutions, ensuring the integrity and protection of these systems must be a priority. With 60% of the world's websites and an increasing share of organization's mission-critical workloads running on Linux, failing to stop malware and other advanced threats on Linux can increasingly impact an organization's reputation and bottom line.

Learn More

Sponsored by Bit9

Linux Backup and Recovery Webinar

Most companies incorporate backup procedures for critical data, which can be restored quickly if a loss occurs. However, fewer companies are prepared for catastrophic system failures, in which they lose all data, the entire operating system, applications, settings, patches and more, reducing their system(s) to “bare metal.” After all, before data can be restored to a system, there must be a system to restore it to.

In this one hour webinar, learn how to enhance your existing backup strategies for better disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible bare-metal recovery solution for UNIX and Linux systems.

Learn More

Sponsored by Storix