From f6890531f8c4905896fa9f452ba0956cae42afe1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E5=BC=9F=E8=B0=83=E8=B0=83=E2=84=A2?=
 <398188662@qq.com>
Date: Mon, 17 Apr 2017 22:15:39 +0800
Subject: [PATCH] =?UTF-8?q?dmesg=E5=91=BD=E4=BB=A4=E6=B7=BB=E5=8A=A0?=
 =?UTF-8?q?=E5=BA=94=E7=94=A8=E5=AE=9E=E4=BE=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 command/dmesg.md | 92 +++++++++++++++++++++++++++---------------------
 1 file changed, 52 insertions(+), 40 deletions(-)

diff --git a/command/dmesg.md b/command/dmesg.md
index f11ad2f351..be21352036 100644
--- a/command/dmesg.md
+++ b/command/dmesg.md
@@ -1,41 +1,53 @@
-dmesg
-===
+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  
-
-```
-dmesg(选项)
-```
-
-### 选项  
-
-```
--c：显示信息后，清除ring buffer中的内容；
--s<缓冲区大小>：预设置为8196，刚好等于ring buffer的大小；
--n：设置记录信息的层级。
-```
-
-### 实例  
-
-```
-[root@localhost ~]# dmesg | head
-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
-BIOS-provided physical RAM map:
- BIOS-e820: 0000000000010000 - 000000000009f400 (usable)
- BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
- BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
- BIOS-e820: 0000000000100000 - 000000007f590000 (usable)
- BIOS-e820: 000000007f590000 - 000000007f5e3000 (ACPI NVS)
- BIOS-e820: 000000007f5e3000 - 000000007f5f0000 (ACPI data)
- BIOS-e820: 000000007f5f0000 - 000000007f600000 (reserved)
- BIOS-e820: 00000000e0000000 - 00000000e8000000 (reserved)
-```
-
-
-<!-- Linux命令行搜索引擎：https://jaywcjlove.github.io/linux-command/ -->
\ No newline at end of file
+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  
+
+```
+dmesg(选项)
+```
+
+### 选项  
+
+```
+-c：显示信息后，清除ring buffer中的内容；
+-s<缓冲区大小>：预设置为8196，刚好等于ring buffer的大小；
+-n：设置记录信息的层级。
+```
+
+### 实例  
+
+```
+[root@localhost ~]# dmesg | head
+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
+BIOS-provided physical RAM map:
+ BIOS-e820: 0000000000010000 - 000000000009f400 (usable)
+ BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
+ BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
+ BIOS-e820: 0000000000100000 - 000000007f590000 (usable)
+ BIOS-e820: 000000007f590000 - 000000007f5e3000 (ACPI NVS)
+ BIOS-e820: 000000007f5e3000 - 000000007f5f0000 (ACPI data)
+ BIOS-e820: 000000007f5f0000 - 000000007f600000 (reserved)
+ BIOS-e820: 00000000e0000000 - 00000000e8000000 (reserved)
+```
+
+查看硬盘基础信息
+
+```bash 
+dmesg | grep sda
+
+[    2.442555] sd 0:0:0:0: [sda] 488281250 512-byte logical blocks: (250 GB/232 GiB)
+[    2.442590] sd 0:0:0:0: [sda] Write Protect is off
+[    2.442592] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
+[    2.442607] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
+[    2.447533]  sda: sda1
+[    2.448503] sd 0:0:0:0: [sda] Attached SCSI disk
+```
+
+<!-- Linux命令行搜索引擎：https://jaywcjlove.github.io/linux-command/ -->