Filtering Android Logcat Output for More Focused Debugging

Filtering Android Logcat Output for More Focused Debugging

22 April 2024 Stephan Petzl Leave a comment Tech-Help

When working with Android’s logcat tool, developers often need to sift through an overwhelming amount of log data to find the information relevant to their debugging efforts. This article provides a guide on how to exclude debug logs from the logcat output to streamline your debugging process.

Understanding Logcat Log Levels

Before diving into the command syntax, it’s important to understand the hierarchy of log levels in Android:

  • V: Verbose (lowest priority)
  • D: Debug
  • I: Info
  • W: Warning
  • E: Error
  • F: Fatal
  • S: Silent (highest priority, no logs are printed)

Logcat allows you to specify a minimum priority level, and it will display all logs at that level and above.

Excluding Debug Logs from Logcat Output

To filter out debug logs, you can use the following command:

adb logcat *:W

This command instructs logcat to display logs with priority ‘Warning’ and above, effectively excluding verbose and debug logs. The asterisk (*) represents all tags, and ‘W’ sets the minimum log level to Warning.

Filtering by Specific Log Levels

If you want to exclude only debug logs but include info logs, you can use the following command:

adb logcat *:I

This command will show all logs at the ‘Info’ priority level and higher, excluding verbose and debug logs.

Special Considerations for Different Shell Environments

If you’re using a shell environment like zsh, which is the default on macOS Catalina and later, you may encounter issues with the asterisk (*) being interpreted as a wildcard for file expansion. To prevent this, you can use one of the following commands:

noglob adb logcat *:E

Or place quotes around the filter expression:

adb logcat '*:E'

Replace ‘E’ with the desired log level as needed.

Advanced Filtering Techniques

For more advanced filtering, such as displaying only specific tags or suppressing logs from other apps, the following command can be used:

adb logcat YourLogTag:D *:S

This command shows only the logs with the tag ‘YourLogTag’ at the ‘Debug’ level while silencing all other tags. You can further refine the output by piping it through grep:

adb logcat YourLogTag:D *:S | grep "D YourLogTag"

This approach filters the logcat output to show only the debug log entries for ‘YourLogTag’.

Integrating Automated Testing with Repeato

In the context of app development and testing, filtering logcat output is just one part of the debugging process. An equally important aspect is ensuring that your app functions correctly across different devices and scenarios. This is where Repeato, a No-code test automation tool, can be a valuable addition to your toolkit.

Repeato not only simplifies the creation and maintenance of automated tests for your iOS and Android apps but also accelerates the editing and running of these tests. With its computer vision and AI capabilities, Repeato works seamlessly with various app frameworks, such as React Native, Flutter, Unity, and more.

Furthermore, Repeato comes with ADB integrated, allowing you to execute ADB commands directly within your test scripts. This integration can be particularly useful when you need to perform actions like resetting app data or manipulating device settings as part of your automated tests.

Conclusion

Effective logcat usage is crucial for efficient Android app debugging. By filtering out unnecessary log levels, you can focus on the information that matters most. And when it comes to automating your testing efforts, Repeato provides a robust solution that complements and enhances your ability to deliver high-quality apps.

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