Master Linux Boot Logs: How to Use dmesg to Inspect and Manage System Messages
Learn how to display, filter, and clear Linux kernel boot messages using the dmesg command, understand its options such as -c, -n, -r, and -s, and see practical examples for checking system startup, disk, and memory information.
dmesg: Display Boot Information
Use the dmesg command to show system boot messages. The kernel stores these messages in a ring buffer, also saved in /var/log/dmesg . Drivers and hardware modules print information that can be viewed with dmesg.
Command Syntax
dmesg [options]Option Meanings
The options are:
-c – display messages then clear the ring buffer.
-n <level> – set the logging level.
-r – print the raw message buffer.
-s <size> – set buffer size (default 8196 bytes).
Examples
(1) Show all boot messages # dmesg (2) View basic disk information # dmesg | grep sda (3) View basic memory information # dmesg | grep memory (4) Clear the dmesg ring buffer
# dmesg -cSigned-in readers can open the original source through BestHub's protected redirect.
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