How do I get the logfile from an Android device?

I would like to pull the log file from a device to my PC. How can I do that?

Logcollector is a good option but you need to install it first.

When I want to get the logfile to send by mail, I usually do the following:

• connect the device to the pc.
• Check that I already setup my os for that particular device.
• Open a terminal
• Run adb shell logcat > log.txt

I hope this code will help someone. It took me 2 days to figure out how to log from device, and then filter it:

public File extractLogToFileAndWeb(){
		//set a file
		Date datum = new Date();
		SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd", Locale.ITALY);
	    String fullName = df.format(datum)+"appLog.log";
	    File file = new File (Environment.getExternalStorageDirectory(), fullName);
	    
	    //clears a file
	    if(file.exists()){
	    	file.delete();
	    }
	    
	    
	    //write log to file
	    int pid = android.os.Process.myPid();
	    try {
	    	String command = String.format("logcat -d -v threadtime *:*");        
	    	Process process = Runtime.getRuntime().exec(command);
	    	
	    	BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
	    	StringBuilder result = new StringBuilder();
	    	String currentLine = null;

	    	while ((currentLine = reader.readLine()) != null) {
	    	       if (currentLine != null && currentLine.contains(String.valueOf(pid))) {
	    	           result.append(currentLine);
	    	           result.append("\n");
	    	        }
	    	}
	    	
	    	FileWriter out = new FileWriter(file);
            out.write(result.toString());
            out.close();
	    	
			//Runtime.getRuntime().exec("logcat -d -v time -f "+file.getAbsolutePath());
		} catch (IOException e) {
			Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_SHORT).show();
		}

	    
	    //clear the log
	    try {
			Runtime.getRuntime().exec("logcat -c");
		} catch (IOException e) {
			Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_SHORT).show();
		}
	    
	    return file;
	}

as pointed by @mehdok

add the permission to the manifest for reading logs

<uses-permission android:name="android.permission.READ_LOGS" />

I would use something of this sort :

$adb logcat -d > logcat.txt

The -d option dumps the entire circular buffer into the text file and if you are looking for a particular action/intent try

$adb logcat -d | grep 'com.whatever.you.are.looking.for' -B 100 -A 100 > shorterlog.txt

Hope this helps :)

For those not interested in USB debugging or using adb there is an easier solution. In Android 6 (Not sure about prior version) there is an option under developer tools: Take Bug Report

Clicking this option will prepare a bug report and prompt you to save it to drive or have it sent in email.

I found this to be the easiest way to get logs. I don't like to turn on USB debugging.

EDIT:

The internal log is a circular buffer in memory. There are actually a few such circular buffers for each of: radio, events, main. The default is main.

To obtain a copy of a buffer, one technique involves executing a command on the device and obtaining the output as a string variable.

SendLog is an open source App which does just this: http://www.l6n.org/android/sendlog.shtml

The key is to run logcat on the device in the embedded OS. It's not as hard as it sounds, just check out the open source app in the link.

Often I get the error "logcat read: Invalid argument". I had to clear the log, before reading from the log.

I do like this:

prompt> cd ~/Desktop
prompt> adb logcat -c
prompt> adb logcat | tee log.txt

I know it's an old question, but I believe still valid even in 2018.

There is an option to Take a bug report hidden in Developer options in every android device.

NOTE: This would dump whole system log

How to enable developer options? see: https://developer.android.com/studio/debug/dev-options

What works for me:

1. Restart your device (in order to create minimum garbage logs for developer to analyze)
2. Reproduce your bug
3. Go to Settings -> Developer options -> Take a bug report
4. Wait for Android system to collect the logs (watch the progressbar in notification)
5. Once it completes, tap the notification to share it (you can use gmail or whetever else)

how to read this? open bugreport-1960-01-01-hh-mm-ss.txt

you probably want to look for something like this:

------ SYSTEM LOG (logcat -v threadtime -v printable -d *:v) ------
--------- beginning of crash
06-13 14:37:36.542 19294 19294 E AndroidRuntime: FATAL EXCEPTION: main

or:

------ SYSTEM LOG (logcat -v threadtime -v printable -d *:v) ------
--------- beginning of main

A simple way is to make your own log collector methods or even just an existing log collector app from the market.

For my apps I made a report functionality which sends the logs to my email (or even to another place - once you get the log you can do whether you want with it).

Here is a simple example about how to get the log file from a device:

• http://code.google.com/p/android-log-collector/

Simple just run the following command to get the output to your terminal:

adb shell logcat

Thanks to user1354692 I could made it more easy, with only one line! the one he has commented:

try {
	File file = new File(Environment.getExternalStorageDirectory(), String.valueOf(System.currentTimeMillis()));
	Runtime.getRuntime().exec("logcat -d -v time -f " + file.getAbsolutePath());}catch (IOException e){}

I have created a small library (.aar) to retrieve the logs by email. You can use it with Gmail accounts. It is pretty simple but works. You can get a copy from here

The site is in Spanish, but there is a PDF with an english version of the product description.

I hope it can help.

> Two steps:

> * Generate the log > * Load Gmail to send the log

.

1. Generate the log

    File generateLog() {
        File logFolder = new File(Environment.getExternalStorageDirectory(), "MyFolder");
        if (!logFolder.exists()) {
            logFolder.mkdir();
        }
        String filename = "myapp_log_" + new Date().getTime() + ".log";
   
        File logFile = new File(logFolder, filename);
   
        try {
            String[] cmd = new String[] { "logcat", "-f", logFile.getAbsolutePath(), "-v", "time", "ActivityManager:W", "myapp:D" };
            Runtime.getRuntime().exec(cmd);
            Toaster.shortDebug("Log generated to: " + filename);
            return logFile;
        }
        catch (IOException ioEx) {
            ioEx.printStackTrace();
        }
   
        return null;
    }
   

2. Load Gmail to send the log

    File logFile = generateLog();
    Intent intent = new Intent(Intent.ACTION_SEND);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    intent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(logFile));
    intent.setType("multipart/");
    startActivity(intent);
   

> References for #1

> - https://stackoverflow.com/a/34883741/2162226 > - https://stackoverflow.com/a/3359857/2162226

~~

> For #2 - there are many different answers out there for how to load the log file to view and send. Finally, the solution here actually worked to both:

> - load Gmail as an option > - attaches the file successfully

> Big thanks to https://stackoverflow.com/a/22367055/2162226 for the correctly working answer

First make sure adb command is executable by setting PATH to android sdk platform-tools:

export PATH=/Users/espireinfolabs/Desktop/soft/android-sdk-mac_x86/platform-tools:$PATH

then run:

adb shell logcat > log.txt

OR first move to adb platform-tools:

cd /Users/user/Android/Tools/android-sdk-macosx/platform-tools 

then run

./adb shell logcat > log.txt