日志信息包括了许多元数据域包括标签和优先级。可以修改日志的输出格式，所以可以显示出特定的元数据域。可以通过 -v选项得到格式化输出日志的相关信息.
brief — Display priority/tag and PID of originating process
(the default format).
process — Display PID only.
tag — Display the priority/tag only.
thread — Display process:thread and priority/tag only.
raw — Display the raw log message, with no other metadata
fields.
time — Display the date, invocation time, priority/tag, and
PID of the originating process.
long — Display all metadata fields and separate messages with
a blank lines. 当启动了logcat，你可以通过-v 选项来指定输出格式:
[adb] logcat [-v <format>]
下面是用 thread来产生的日志格式:
adb logcat -v thread
需要注意的是你只能-v 选项来规定输出格式
option.