CentOS command -- dmesg

CentOS command -- dmesg

1. Command Format:

# Dmesg (parameter)

2. command functions:

Displays the boot information. The kernel stores the boot information in the ring buffer. You can use dmesg to view the information if you cannot view it at startup. The boot information is also saved in the/var/log directory and named dmesg.

3. parameters:

-C: After the information is displayed, clear the content in the ring buffer. -N: set the record information level. For example, if-n 1 is the lowest level, only kernel panic information is displayed on the console.

4. instance:

# Dmesg | less page display of boot information # dmesg | grep-I sda displays hard disk devices detected by the system, such as tty, USB, memory, and dma. # Tail-f/var/log/dmesg monitors dmesg log output in real time. # Watch "dmesg | tail-20" monitors dmesg log output in real time.

Note:

1) if hard disk performance is poor, you can use dmesg to check whether they are running in DMA mode: dmesg | grep DMA 2) to detect the loading of system kernel modules, for example, to detect ACPI loading, use dmesg | grep acpi 3) You can use mail-s "Boot Log Of xxx Server" user@xxx.com <messages to send these Log information