$ adb logcat -h Unrecognized Option h Usage: logcat [options] [filterspecs] options include: -s Set default filter to silent. Like specifying filterspec '*:S' -f <filename> Log to file. Default is stdout --file=<filename> -r <kbytes> Rotate log every kbytes. Requires -f --rotate-kbytes=<kbytes> -n <count> Sets max number of rotated logs to <count>, default 4 --rotate-count=<count> -v <format> Sets the log print format, where <format> is: --format=<format> brief color epoch long monotonic printable process raw tag thread threadtime time uid usec UTC year zone -D print dividers between each log buffer --dividers -c clear (flush) the entire log and exit --clear -d dump the log and then exit (don't block) -e <expr> only print lines where the log message matches <expr> --regex <expr> where <expr> is a regular expression -m <count> quit after printing <count> lines. This is meant to be --max-count=<count> paired with --regex, but will work on its own. --print paired with --regex and --max-count to let content bypass regex filter but still stop at number of matches. -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...' 'YYYY-MM-DD hh:mm:ss.mmm...' or 'sssss.mmm...' format -g get the size of the log's ring buffer and exit --buffer-size -G <size> set size of log ring buffer, may suffix with K or M. --buffer-size=<size> -L dump logs from prior to last reboot --last -b <buffer> Request alternate ring buffer, 'main', 'system', 'radio', --buffer=<buffer> 'events', 'crash', 'default' 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. --binary -S output statistics. --statistics -p print prune white and ~black list. Service is specified as --prune 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 --prune='<list> ...' printed above. Must be quoted. --pid=<pid> Only prints logs from the given pid. --wrap Sleep for 2 hours or when buffer about to wrap whichever comes first. Improves efficiency of polling by providing an about-to-wrap wakeup. filterspecs are a series of <tag>[:priority] where <tag> is a log component tag (or * for all) and priority is: V Verbose (default for <tag>) D Debug (default for '*') I Info W Warn E Error F Fatal S Silent (suppress all output) '*' by itself means '*:D' and <tag> by itself means <tag>:V. If no '*' filterspec or -s on command line, all filter defaults to '*:V'. eg: '*:S <tag>' prints only <tag>, '<tag>:S' suppresses all <tag> log messages. If not specified on the command line, filterspec is set from ANDROID_LOG_TAGS. If not specified with -v on command line, format is set from ANDROID_PRINTF_LOG or defaults to "threadtime"
$ adb logcat -g main: ring buffer is 16Mb (3Mb consumed), max entry is 5120b, max payload is 4068b system: ring buffer is 16Mb (12Mb consumed), max entry is 5120b, max payload is 4068b crash: ring buffer is 16Mb (1Kb consumed), max entry is 5120b, max payload is 4068b