1page.title=logcat 2parent.title=Tools 3parent.link=index.html 4@jd:body 5 6 <p>The Android logging system provides a mechanism for collecting and viewing system debug 7 output. Logs from various applications and portions of the system are collected in a series of 8 circular buffers, which then can be viewed and filtered by the <code>logcat</code> command. You can use 9 <code>logcat</code> from an ADB shell to view the log messages.</p> 10 11 <p>For complete information about logcat options and filtering specifications, see 12 <a href="{@docRoot}tools/debugging/debugging-log.html">Reading and Writing Logs</a>.</p> 13 14 <p>For more information on accessing <code>logcat</code> from DDMS, instead of the command line, see 15 <a href="{@docRoot}tools/debugging/ddms.html">Using DDMS</a>. </p> 16 17 <h3>Syntax</h3> 18 <pre> 19[adb] logcat [<option>] ... [<filter-spec>] ... 20</pre> 21 22 <p>You can run <code>logcat</code> as an adb command or directly in a shell prompt 23 of your emulator or connected device. To view log output using adb, navigate to your SDK 24 <code>platform-tools/</code> directory and execute:</p> 25 <pre> 26$ adb logcat 27</pre> 28 29 <p>You can create a shell connection to a device and execute:</p> 30 <pre> 31$ adb shell 32# logcat 33</pre> 34 35 <h3>Options</h3> 36 <p>The following table describes the command line options of <code>logcat</code>.</p> 37 38 <table> 39 <tr> 40 <th>Option</th> 41 42 <th>Description</th> 43 </tr> 44 45 <tr> 46 <td><code>-b <buffer></code></td> 47 48 <td>Loads an alternate log buffer for viewing, such as <code>event</code> or 49 <code>radio</code>. The <code>main</code> buffer is used by default. See <a href= 50 "{@docRoot}tools/debugging/debugging-log.html#alternativeBuffers">Viewing Alternative Log Buffers</a>.</td> 51 </tr> 52 53 <tr> 54 <td><code>-c</code></td> 55 56 <td>Clears (flushes) the entire log and exits.</td> 57 </tr> 58 59 <tr> 60 <td><code>-d</code></td> 61 62 <td>Dumps the log to the screen and exits.</td> 63 </tr> 64 65 <tr> 66 <td><code>-f <filename></code></td> 67 68 <td>Writes log message output to <code><filename></code>. The default is 69 <code>stdout</code>.</td> 70 </tr> 71 72 <tr> 73 <td><code>-g</code></td> 74 75 <td>Prints the size of the specified log buffer and exits.</td> 76 </tr> 77 78 <tr> 79 <td><code>-n <count></code></td> 80 81 <td>Sets the maximum number of rotated logs to <code><count></code>. The default value 82 is 4. Requires the <code>-r</code> option.</td> 83 </tr> 84 85 <tr> 86 <td><code>-r <kbytes></code></td> 87 88 <td>Rotates the log file every <code><kbytes></code> of output. The default value is 89 16. Requires the <code>-f</code> option.</td> 90 </tr> 91 92 <tr> 93 <td><code>-s</code></td> 94 95 <td>Sets the default filter spec to silent.</td> 96 </tr> 97 98 <tr> 99 <td><code>-v <format></code></td> 100 101 <td>Sets the output format for log messages. The default is <code>brief</code> format. For a 102 list of supported formats, see <a href="{@docRoot}tools/debugging/debugging-log.html#outputFormat">Controlling Log Output 103 Format</a>.</td> 104 </tr> 105 </table> 106