adb shell ls /system/bin
可以查看可用adb shell 命令。 并且大部分命令 可以通过 --help 获得参数帮助。例如，
adb shell cat --help
Toybox 0.8.4-android multicall binary: https://landley.net/toybox (see toybox --help)
usage: cat [-etuv] [FILE...]
Copy (concatenate) files to stdout. If no files listed, copy from stdin.
Filename "-" is a synonym for stdin.
-e Mark each newline with $
-t Show tabs as ^I
-u Copy one byte at a time (slow)
-v Display nonprinting characters as escape sequences with M-x for
high ascii characters (>127), and ^x for other nonprinting chars
adb shell screenrecord --help
Usage: screenrecord [options] <filename>
Android screenrecord v1.3. Records the device's display to a .mp4 file.
Options:
--size WIDTHxHEIGHT
Set the video size, e.g. "1280x720". Default is the device's main
display resolution (if supported), 1280x720 if not. For best results,
use a size supported by the AVC encoder.
--bit-rate RATE
Set the video bit rate, in bits per second. Value may be specified as
bits or megabits, e.g. '4000000' is equivalent to '4M'. Default 20Mbps.
--bugreport
Add additional information, such as a timestamp overlay, that is helpful
in videos captured to illustrate bugs.
--time-limit TIME
Set the maximum recording time, in seconds. Default / maximum is 180.
--display-id ID
specify the physical display ID to record. Default is the primary display.
see "dumpsys SurfaceFlinger --display-id" for valid display IDs.
--verbose
Display interesting information on stdout.
--help
Show this message.
Recording continues until Ctrl-C is hit or the time limit is reached.
