adb logcat 命令使用说明

logcat命令主要用来获取Android运行时的日志，通过不同的参数可以获取可以获取整个系统不同层面的日志信息。

下面将先对各个参数进行简单介绍，之后会列举一下Android开发过程中常用场景日志抓取命令。  

–help

主要用来获取logcat命令帮助信息。

命令：adb logcat -help

[D:~]$ adb logcat -help
logcat: invalid option -- h
Unrecognized Option
Usage: logcat [options] [filterspecs]
options include:
  -s              Set default filter to silent.
                  Like specifying filterspec '*:s'
  -f <filename>   Log to file. Default to stdout
  -r [<kbytes>]   Rotate log every kbytes. (16 if unspecified). Requires -f
  -n <count>      Sets max number of rotated logs to <count>, default 4
  -v <format>     Sets the log print format, where <format> is one of:

                  brief process tag thread raw time threadtime long

  -c              clear (flush) the entire log and exit
  -d              dump the log and then exit (don't block)
  -t <count>      print only the most recent <count> lines (implies -d)
  -t '<time>'     print most recent lines since specified time (implies -d)
  -T <count>      print only the most recent <count> lines (does not imply -d)
  -T '<time>'     print most recent lines since specified time (not imply -d)
                  count is pure numerical, time is 'MM-DD hh:mm:ss.mmm'
  -g              get the size of the log's ring buffer and exit
  -b <buffer>     Request alternate ring buffer, 'main', 'system', 'radio',
                  'events', 'crash' or 'all'. Multiple -b parameters are
                  allowed and results are interleaved. The default is
                  -b main -b system -b crash.
  -B              output the log in binary.
  -S              output statistics.
  -G <size>       set size of log ring buffer, may suffix with K or M.
  -p              print prune white and ~black list. Service is specified as
                  UID, UID/PID or /PID. Weighed for quicker pruning if prefix
                  with ~, otherwise weighed for longevity if unadorned. All
                  other pruning activity is oldest first. Special case ~!
                  represents an automatic quicker pruning for the noisiest
                  UID as determined by the current statistics.
  -P '<list> ...' set prune white and ~black list, using same format as
                  printed above. Must be quoted.

filterspecs are a series of 
  <tag>[:priority]

where <tag> is a log component tag (or * for all) and priority is:
  V    Verbose
  D    Debug
  I    Info
  W    Warn
  E    Error
  F    Fatal
  S    Silent (supress all output)

'*' means '*:d' and <tag> by itself means <tag>:v

If not specified on the commandline, filterspec is set from ANDROID_LOG_TAGS.
If no filterspec is found, filter defaults to '*:I'

If not specified with -v, format is set from ANDROID_PRINTF_LOG
or defaults to "brief"

选项解析

-s: 设置输出日志的标签, 只显示该标签的日志;

清空日志缓存

adb logcat -c

执行该命令后，将清除系统中的所有日志缓存。

radio日志获取

adb logcat -v time -b radio

执行该命令后，就是打印出带时间格式的radio日志。