Can anyone tell me how does the adb shell dumpsys work internally? I suppose this command reads the /proc fs somehow, but this is just my understanding.
It seems that android sdk 19 onwards, following command is not supported-
adb shell dumpsys batteryinfo
It has been replaced by
adb shell dumpsys batterystats
I would like to know if any documentation (link) is available, where detailed information about this can be found.
If you take a look at the source code for dumpsys, you can see that it simply requests a instance of the service from the default service manager and then calls the service dump() method (which is an interface of IBinder) passing STDOUT and the command line args:
sp<IServiceManager> sm = defaultServiceManager();
...
sp<IBinder> service = sm->checkService(services[i]);
...
int err = service->dump(STDOUT_FILENO, args);
In your example above, the service in question would appear to have been renamed from batteryinfo to batterystats