In Android, the logcat command provides a way to view system debug output. Logs from various applications and portions of the system are collected in a series of circular buffers, which can then be viewed and filtered by using this command:

adb.exe logcat
--------- beginning of system
 09-17 10:04:52.463 2477 2477 I vold : Vold 3.0 (the awakening) firing up
 09-17 10:04:52.463 2477 2477 V vold : Detected support for: exfat ext4 f2fs ntfs vfat
 09-17 10:04:52.475 2477 2482 D vold : e4crypt_init_user0
 09-17 10:04:52.475 2477 2482 D vold : e4crypt_prepare_user_storage for volume null, user 0, serial 0, flags 1
 09-17 10:04:52.475 2477 2482 D vold : Preparing: /data/system/users/0
 09-17 10:04:52.476 2477 2482 D vold : Preparing: /data/misc/profiles/cur/0
 09-17 10:04:52.476 2477 2482 D vold : Preparing: /data/system_de/0
 09-17 10:04:52.477 2477 2482 D vold : Preparing: /data/misc_de/0
 09-17 10:04:52.477 2477 2482 D vold : Preparing: /data/user_de/0
 09-17 10:04:52.477 2477 2482 D vold : e4crypt_unlock_user_key 0 serial=0 token_present=0
 09-17 10:04:52.712 2477 2480 D vold : Disk at 7:64 changed
 09-17 10:04:52.933 2590 2590 I [email protected]: Wifi Hal is booting up...
 09-17 10:04:53.023 2619 2619 I installd: installd firing up
 09-17 10:04:53.166 2627 2627 I wificond: wificond is starting up...
 09-17 10:04:53.285 2626 2666 I /system/bin/storaged: storaged: Start
 09-17 10:04:55.120 2760 2760 I SystemServer: InitBeforeStartServices
 09-17 10:04:55.122 2760 2760 I SystemServer: Entered the Android system server!
 09-17 10:04:55.358 2760 2760 I SystemServer: StartServices
 09-17 10:04:55.358 2760 2760 I SystemServer: Reading configuration...
 09-17 10:04:55.358 2760 2760 I SystemServer: ReadingSystemConfig
 09-17 10:04:55.359 2760 2760 I SystemServer: StartInstaller
 09-17 10:04:55.360 2760 2760 I SystemServiceManager: Starting com.android.server.pm.Installer
 09-17 10:04:55.362 2760 2760 I SystemServer: DeviceIdentifiersPolicyService
 09-17 10:04:55.362 2760 2760 I SystemServiceManager: Starting com.android.server.os.DeviceIdentifiersPolicyService
 09-17 10:04:55.363 2760 2760 I SystemServer: StartActivityManager
 09-17 10:04:55.363 2760 2760 I SystemServiceManager: Starting com.android.server.am.ActivityManagerService$Lifecycle
 09-17 10:04:55.382 2760 2760 I ActivityManager: Memory class: 192
 09-17 10:04:55.406 2760 2760 D BatteryStatsImpl: Reading daily items from /data/system/batterystats-daily.xml
 09-17 10:04:55.421 2760 2777 E BatteryExternalStatsWorker: no controller energy info supplied for telephony
...

The log message shown here is just a sample message and, during investigation, logs need to be carefully analyzed to gather information on location details, data/time information, application details, and so on. Each log begins with a message type indicator as described in the following table: