"adb logcat" Command Options and Log Buffers

Android Tutorials - Herong's Tutorial Examples

∟Using "adb logcat" Command for Debugging

∟"adb logcat" Command Options and Log Buffers

This section describes the 'adb logcat' command options to dump and manage log buffers: main, events, and radio. An example is given to dump logs into a set of rotated log files.

To better use the "adb logcat" command, we need to look at its options:

"adb logcat -b <buffer>" - Loads an alternate log buffer for viewing, such as event or radio. The main buffer is used by default. There are 3 log buffers on the Android system: "main", "events", and "radio". The default buffer is "main".
"adb logcat -c" - Clears (flushes) the entire log and exits.
"adb logcat -d" - Dumps the log to the screen and exits.
"adb logcat -f <filename>" - Writes log message output to a file. The default is the "stdout - Standard Output".
"adb logcat -g" - Prints the size of the specified log buffer and exits.
"adb logcat -n <count>" - Sets the maximum number of rotated logs to <count>. The default value is 4. Requires the -r option.
"adb logcat -r <kbytes>" - Rotates the log file every <kbytes> of output. The default value is 16. Requires the -f option.
"adb logcat -s" - Sets the default filter spec to silent.
"adb logcat -v <format>" - Sets the output format for log messages. The default is brief format.

Here are two examples of using "adb logcat" options:

1. To show the size of the default log buffer (main) and clear it on the connected device:

C:\herong\>\local\android-sdk-windows\platform-tools\adb logcat -g
main: ring buffer is 256Kb (212Kb consumed), max entry is 5120b, ...
system: ring buffer is 256Kb (70Kb consumed), max entry is 5120b,...
crash: ring buffer is 256Kb (0b consumed), max entry is 5120b, ma...

C:\herong\>\local\android-sdk-windows\platform-tools\adb logcat -c

C:\herong\>\local\android-sdk-windows\platform-tools\adb logcat -g
main: ring buffer is 256Kb (98b consumed), max entry is 5120b, ma...
system: ring buffer is 256Kb (0b consumed), max entry is 5120b, m...
crash: ring buffer is 256Kb (0b consumed), max entry is 5120b, ma...

2. To continuously dump log entries to a set of 8 rotated log files of 1 MB each on the file system of the connected device:

C:\herong\>\local\android-sdk-windows\platform-tools\adb logcat \
   -f /sdcard/Download/Android.log -r 1024 -n 8

(leave it running)

See next tutorials on how to control the format of the "adb logcat" output.

Table of Contents

About This Book

Installing JDK 1.8 on Windows System

Installation of Android SDK R24 and Emulator

Installing Apache Ant 1.9 on Windows System

Developing First Android Application - HelloAndroid

Android Application Package (APK) Files

Android Debug Bridge (adb) Tool

Android File Systems

AboutAndroid - Application to Retrieve System Information

android.app.Activity Class and Activity Lifecycle

View Objects and Layout Resource Files

►Using "adb logcat" Command for Debugging

"adb logcat" Command - Displaying System Logs

►"adb logcat" Command Options and Log Buffers

"adb logcat -v" Command - Log Format Control

"adb logcat" Command Arguments - Output Filters

Using "adb logcat" Command to Track the Lifecycle of an Application

Java Exceptions in AndroidRuntime Error Log

Build Process and Package File Content

Building Your Own Web Browser

Android Command Line Shell

Samsung Galaxy Tab 3 Mini Tablet

USB Debugging Applications on Samsung Tablet

Android Tablet - LG-V905R

USB Debugging Applications on LG-V905R Tablet

Android Phone - LG-P925g

USB Debugging Applications on LG-P925g Phone

Archived Tutorials

References

Full Version in PDF/EPUB