1# dmesg<a name="ZH-CN_TOPIC_0000001179845915"></a> 2 3- [命令功能](#section4643204919313) 4- [命令格式](#section6553153635) 5- [参数说明](#section208971157532) 6- [使用指南](#section213115219413) 7- [使用实例](#section13736564418) 8- [输出说明](#section194005101413) 9 10## 命令功能<a name="section4643204919313"></a> 11 12dmesg命令用于控制内核dmesg缓存区。 13 14## 命令格式<a name="section6553153635"></a> 15 16dmesg 17 18dmesg \[_-c/-C/-D/-E/-L/-U_\] 19 20dmesg -s \[_size_\] 21 22dmesg -l \[_level_\] 23 24dmesg \> \[_fileA_\] 25 26## 参数说明<a name="section208971157532"></a> 27 28**表 1** 参数说明 29 30<a name="table3900mcpsimp"></a> 31<table><thead align="left"><tr id="row3906mcpsimp"><th class="cellrowborder" valign="top" width="21%" id="mcps1.2.4.1.1"><p id="p3908mcpsimp"><a name="p3908mcpsimp"></a><a name="p3908mcpsimp"></a>参数</p> 32</th> 33<th class="cellrowborder" valign="top" width="52%" id="mcps1.2.4.1.2"><p id="p3910mcpsimp"><a name="p3910mcpsimp"></a><a name="p3910mcpsimp"></a>参数说明</p> 34</th> 35<th class="cellrowborder" valign="top" width="27%" id="mcps1.2.4.1.3"><p id="p3912mcpsimp"><a name="p3912mcpsimp"></a><a name="p3912mcpsimp"></a>取值范围</p> 36</th> 37</tr> 38</thead> 39<tbody><tr id="row3913mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3915mcpsimp"><a name="p3915mcpsimp"></a><a name="p3915mcpsimp"></a>-c</p> 40</td> 41<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3917mcpsimp"><a name="p3917mcpsimp"></a><a name="p3917mcpsimp"></a>打印缓存区内容并清空缓存区。</p> 42</td> 43<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3919mcpsimp"><a name="p3919mcpsimp"></a><a name="p3919mcpsimp"></a>N/A</p> 44</td> 45</tr> 46<tr id="row3920mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3922mcpsimp"><a name="p3922mcpsimp"></a><a name="p3922mcpsimp"></a>-C</p> 47</td> 48<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3924mcpsimp"><a name="p3924mcpsimp"></a><a name="p3924mcpsimp"></a>清空缓存区。</p> 49</td> 50<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3926mcpsimp"><a name="p3926mcpsimp"></a><a name="p3926mcpsimp"></a>N/A</p> 51</td> 52</tr> 53<tr id="row3927mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3929mcpsimp"><a name="p3929mcpsimp"></a><a name="p3929mcpsimp"></a>-D/-E</p> 54</td> 55<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3931mcpsimp"><a name="p3931mcpsimp"></a><a name="p3931mcpsimp"></a>关闭/开启控制台打印。</p> 56</td> 57<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3933mcpsimp"><a name="p3933mcpsimp"></a><a name="p3933mcpsimp"></a>N/A</p> 58</td> 59</tr> 60<tr id="row3934mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3936mcpsimp"><a name="p3936mcpsimp"></a><a name="p3936mcpsimp"></a>-L/-U</p> 61</td> 62<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3938mcpsimp"><a name="p3938mcpsimp"></a><a name="p3938mcpsimp"></a>关闭/开启串口打印。</p> 63</td> 64<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3940mcpsimp"><a name="p3940mcpsimp"></a><a name="p3940mcpsimp"></a>N/A</p> 65</td> 66</tr> 67<tr id="row3941mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3943mcpsimp"><a name="p3943mcpsimp"></a><a name="p3943mcpsimp"></a>-s size</p> 68</td> 69<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3945mcpsimp"><a name="p3945mcpsimp"></a><a name="p3945mcpsimp"></a>设置缓存区大小 size是要设置的大小。</p> 70</td> 71<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3947mcpsimp"><a name="p3947mcpsimp"></a><a name="p3947mcpsimp"></a>N/A</p> 72</td> 73</tr> 74<tr id="row3948mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3950mcpsimp"><a name="p3950mcpsimp"></a><a name="p3950mcpsimp"></a>-l level</p> 75</td> 76<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3952mcpsimp"><a name="p3952mcpsimp"></a><a name="p3952mcpsimp"></a>设置缓存等级。</p> 77</td> 78<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3954mcpsimp"><a name="p3954mcpsimp"></a><a name="p3954mcpsimp"></a>0 - 5</p> 79</td> 80</tr> 81<tr id="row3955mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3957mcpsimp"><a name="p3957mcpsimp"></a><a name="p3957mcpsimp"></a>> fileA</p> 82</td> 83<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3959mcpsimp"><a name="p3959mcpsimp"></a><a name="p3959mcpsimp"></a>将缓存区内容写入文件。</p> 84</td> 85<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3961mcpsimp"><a name="p3961mcpsimp"></a><a name="p3961mcpsimp"></a>N/A</p> 86</td> 87</tr> 88</tbody> 89</table> 90 91## 使用指南<a name="section213115219413"></a> 92 93- 该命令依赖于LOSCFG\_SHELL\_DMESG，使用时通过menuconfig在配置项中开启"Enable Shell dmesg"： 94 95 Debug ---\> Enable a Debug Version ---\> Enable Shell ---\> Enable Shell dmesg 96 97- dmesg参数缺省时，默认打印缓存区内容。 98- 各“ - ”选项不能混合使用。 99 1. 写入文件需确保已挂载文件系统。 100 2. 关闭串口打印会影响shell使用，建议先连接telnet再尝试关闭串口。 101 102 103## 使用实例<a name="section13736564418"></a> 104 105举例： 106 107输入dmesg \> /usr/dmesg.log。 108 109## 输出说明<a name="section194005101413"></a> 110 111**图 1** dmesg重定向到文件。<a name="fig11150135113566"></a> 112 113 114