What is dmesg in linux

What if you want to know info related to these kernel activities? Well, there exists a command - dubbed dmesg - that you can use if you want to access messages printed by kernel. In this tutorial, we will understand how the dmesg tool works using some easy to understand examples. If you run dmesg on your system, you'll observe it outputs plethora of information. Depending upon what you're looking for, you may want to filter or limit the output.

For its part, dmesg offers you this ability through 'levels. So for example, if you want to limit the output to only error and warnings, you can do that in the following way:. Sometimes, you may want a timestamp to be associated with the messages dmesg produces.

This can be done using the -T command line option, which produces human readable timestamps. Suppose you want dmesg to only display info related to eth0 interface. Here's how you can do that:. If you want to limit dmesg's output only to userspace messages, use the -u command line option.

Millions of people visit TecMint! If you like what you are reading, please consider buying us a coffee or 2 as a token of appreciation. We are thankful for your never ending support. New to Linux, how do I review the memory of my computer using the dmesg command? The preferred way to monitor dmesg in realtime is: dmesg —follow to reduce system load you should use the other two solutions only if the option —follow or -w is not part of your dmesg command.

Have a question or suggestion? Please leave a comment to start the discussion. Please keep in mind that all comments are moderated and your email address will NOT be published. Save my name, email, and website in this browser for the next time I comment. Notify me of followup comments via e-mail. You can also subscribe without commenting. This site uses Akismet to reduce spam.

Learn how your comment data is processed. Every message logged to the kernel ring buffer has a level attached to it. The level represents the importance of the information in the message.

The levels are:. We can make dmesg extract messages that match a particular level by using the -l level option and passing the name of the level as a command-line parameter. All of the messages that are listed are informational messages. We can ask dmesg to filter its output to only show messages in a specific facility. To do so, we must use the -f facility option:. As we did with the levels, we can ask dmesg to list messages from more than one facility at once:. The -x decode option makes dmesg show the facility and level as human-readable prefixes to each line.

If you are having issues with a piece of hardware not being recognized or not behaving properly, dmesg may throw some light on the issue. Browse All iPhone Articles Browse All Mac Articles Do I need one? Browse All Android Articles Browse All Smart Home Articles Customize the Taskbar in Windows Browse All Microsoft Office Articles What Is svchost. Browse All Privacy and Security Articles Browse All Linux Articles Browse All Buying Guides.

Best Portable Monitors. Best Gaming Keyboards. Best Drones. Best 4K TVs. Best iPhone 13 Cases. Best Tech Gifts for Kids Aged Best 8K TVs.

Best VR Headsets. Best iPad Mini Cases. Best Gifts for Cutting the Cord. Best Bluetooth Speakers. Awesome PC Accessories. Best Linux Laptops. Best Gaming Monitors.