1# dmesg<a name="EN-US_TOPIC_0000001179845915"></a> 2 3- [Command Function](#section4643204919313) 4- [Syntax](#section6553153635) 5- [Parameters](#section208971157532) 6- [Usage](#section213115219413) 7- [Example](#section13736564418) 8- [Output](#section194005101413) 9 10## Command Function<a name="section4643204919313"></a> 11 12This command is used to control the dmesg buffer of the kernel. 13 14## Syntax<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## Parameters<a name="section208971157532"></a> 27 28**Table 1** Parameter description 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>Parameter</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>Description</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>Value Range</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>Prints content in the buffer and clears the buffer.</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>Clears the buffer.</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>Enables or disables printing to the console.</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>Enables or disables printing via the serial port.</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>Sets the size of the buffer.</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>Sets the buffering level.</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>Writes the content in the buffer to a file.</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## Usage<a name="section213115219413"></a> 92 93- This command depends on **LOSCFG\_SHELL\_DMESG**. Before using this command, select **Enable Shell dmesg** on **menuconfig**. 94 95 Debug ---\> Enable a Debug Version ---\> Enable Shell ---\> Enable Shell dmesg 96 97- If the parameters are not specified, all content in the buffer is printed. 98- The parameters followed by hyphens \(-\) are mutually exclusive. 99 1. Before writing content to a file, ensure that the file system has been mounted. 100 2. Disabling the serial port printing will adversely affect the shell. You are advised to set up a connection using Telnet before disabling the serial port. 101 102 103## Example<a name="section13736564418"></a> 104 105Example: 106 107Run **dmesg \> /usr/dmesg.log**. 108 109## Output<a name="section194005101413"></a> 110 111**Figure 1** Writing dmesg content to a file<a name="fig11150135113566"></a> 112 113 114
