Update README.md

Add logcat filtering by process id.

README.md

@@ -45,7 +45,7 @@ Easy starting points are also reviewing [pull requests](https://github.com/nextc
 #### With a computer:
 - connect the device via USB
 - open command prompt/terminal
-- enter `adb logcat > logcatOutput.txt` to save the output to this file
+- enter `adb logcat | grep "$(adb shell ps | grep com.nextcloud.client | awk '{print $2}')" > logcatOutput.txt` to save the output to this file
 
 **Note:** You must have [adb](https://developer.android.com/studio/releases/platform-tools.html) installed first!
 
@@ -53,6 +53,7 @@ Easy starting points are also reviewing [pull requests](https://github.com/nextc
 - open terminal app *(can be enabled in developer options)*
 - get root access via "su"
 - enter `logcat -d -f /sdcard/logcatOutput.txt`
+- you will have to filter the output manually, as above approach is not working on device
 
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