NAME
dmesg - print or control the kernel ring buffer
总览
dmesg [ -c ] [ -n 级别 ] [ -s 缓冲区大小 ]
描述
dmesg 用于检测和控制内核环缓冲。
程序用来帮助用户了解系统的启动信息。用户只需使用命令：
- dmesg > boot.messages
然后将文件 boot.messages 邮寄给某些可以帮你调试系统的人。而无须手工拷贝系统启动信息。
选项
- -c
- 当完成打印显示后清除环缓冲内的内容。
- -s缓冲区大小
- 定义一个大小为"缓冲区大小"的缓冲区用于查询内核环缓冲区。默认大小为 8196（此大小与 2.0.33 和 2.1.103 内核的默认 syslog 缓冲区大小一致），如果你设置了一个大于默认值的环缓冲区，那你就可以用这个选项定义一个相当的缓冲区来查看完整的环缓冲区内容。
- -n级别
- 设置 级别 为记录控制台启动信息的级别。比如， -n 1 指的就是将此级别设为***级，除了内核恐慌信息之外不会向控制台显示信息。所有级别的启动信息还将记录到 /proc/kmsg, 文件中，因此， syslogd(8) 同样可以用来对信息的输出进行控制。当使用 -n 选项时， dmesg 将 不会 清除内核环缓冲区中的内容。当同时使用以上两个选项时，只有***一个选项才会产生效果。
又见
syslogd(8)
#p#
NAME
dmesg - print or control the kernel ring buffer
SYNOPSIS
dmesg [ -c ] [ -n level ] [ -s bufsize ]
DESCRIPTION
dmesg 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
and mail the boot.messages file to whoever can debug their problem.
OPTIONS
- -c
- Clear the ring buffer contents after printing.
- -sbufsize
- 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.
- -nlevel
- Set the level at which logging of messages is done to the console. For example, -n 1 prevents all messages, expect panic messages, from appearing on the console. All levels of messages are still written to /proc/kmsg, so syslogd(8) can still be used to control exactly where kernel messages appear. When the -n option is used, dmesg will not print or clear the kernel ring buffer.
When both options are used, only the last option on the command line will have an effect.
SEE ALSO
syslogd(8)
