dmesg(8) -- Linux man page
NAMEdmesg - print or control the kernel ring buffer
SYNOPSISdmesg [ -c ] [ -n level ] [ -s bufsize ]
DESCRIPTIONdmesg is used to examine or control the kernel ring buffer.
The program helps users to print out their bootup messages. Instead of copying the messages by hand, the user need only:
- dmesg > boot.messages
- Clear the ring buffer contents after printing.
- Use a buffer of size bufsize to query the kernel ring buffer. This is 16392 by default. (The default kernel syslog buffer size was 4096 at first, 8192 since 1.3.54, 16384 since 2.1.113.) If you have set the kernel buffer to be larger than the default then this option can be used to view the entire buffer.
at which logging of messages is done to the console. For example,
prevents all messages, expect panic messages, from appearing on the
console. All levels of messages are still written to
can still be used to control exactly where kernel messages appear. When
option is used,
print or clear the kernel ring buffer.
When both options are used, only the last option on the command line will have an effect.
AUTHORTheodore Ts'o (email@example.com)