How to get adb logcat to filter ONLY by specific app (package name)

Would like to know how can I get the adb logcat of ONLY certain app, and all its errors and messages associated. I've tried before with adb logcat -c; adb logcat | grep com.fitbit.FitbitMobile, but the thing is, it forces a grep on EVERY line, and sometimes there's a crash that involves multiline where needed information gets omitted. I've tried the command on page Displaying and filtering with Logcat , however doesn't work. It just gets everything: adb logcat -c && adb logcat com.fitbit.FitbitMobile:V I've tried also the filtering option on Android Developers Documentation , but just mutes everything: adb logcat com.fitbit.FitbitMobile:D *:S Others commands that get the pid are not useful if the app is not running when I run logcat, and crashes immediately and is relaunched with a different pid. Any ideas about the proper format?