• dmesg
    • 补充说明
      • 语法
      • 选项
      • 实例

    dmesg

    显示Linux系统启动信息

    补充说明

    dmesg命令 被用于检查和控制内核的环形缓冲区。kernel会将开机信息存储在ring buffer中。您若是开机时来不及查看信息，可利用dmesg来查看。开机信息保存在/var/log/dmesg文件里。

    语法

    1. dmesg(选项)

    选项

    1. -c：显示信息后，清除ring buffer中的内容；
    2. -s<缓冲区大小>：预设置为8196，刚好等于ring buffer的大小；
    3. -n：设置记录信息的层级。

    实例

    1. [root@localhost ~]# dmesg | head
    2. Linux version 2.6.18-348.6.1.el5 (mockbuild@builder17.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-54)) #1 SMP Tue May 21 15:34:22 EDT 2013
    3. BIOS-provided physical RAM map:
    4.  BIOS-e820: 0000000000010000 - 000000000009f400 (usable)
    5.  BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
    6.  BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
    7.  BIOS-e820: 0000000000100000 - 000000007f590000 (usable)
    8.  BIOS-e820: 000000007f590000 - 000000007f5e3000 (ACPI NVS)
    9.  BIOS-e820: 000000007f5e3000 - 000000007f5f0000 (ACPI data)
    10.  BIOS-e820: 000000007f5f0000 - 000000007f600000 (reserved)
    11.  BIOS-e820: 00000000e0000000 - 00000000e8000000 (reserved)

    查看硬盘基础信息

    1. dmesg | grep sda
    3. [    2.442555] sd 0:0:0:0: [sda] 488281250 512-byte logical blocks: (250 GB/232 GiB)
    4. [    2.442590] sd 0:0:0:0: [sda] Write Protect is off
    5. [    2.442592] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
    6. [    2.442607] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
    7. [    2.447533]  sda: sda1
    8. [    2.448503] sd 0:0:0:0: [sda] Attached SCSI disk