一、adb实现原理
adb的目的是想仅在PC端执行adb操作来获取手机里面的文件或向手机内部发送文件。这是通过Ubuntu中adb操作作为客户端与Ubuntu中运行的adb service交互，Ubuntu中运行的adb service与手机中运行的adbd守护进程交互实现的。
设备端(eg:手机)在启动后会启动一个名为adbd的守护进程，来监听PC通过adb发来的请求。Ubuntu中默认是不会启动启动adb服务的，但是执行adb devices的时候若是adb server还没有启动，就会通过"adb -P 5037 fork-server server"来启动adb服务服务。此后，Ubuntu中运行adb就作为client向Ubuntu中的adb service发起请求，然后Ubuntu中的adb server与手机里面的adbd守护进程通信。
二、adb操作
1.Ubuntu要获取手机中的一个文件：
# adb devices * daemon not running. starting it now on port 5037 * 执行的时候adb server还没有运行，然后就启动adb server。 * daemon started successfully * List of devices attached FA4412DBA4120433 device 表示一个device已经attach到Ubuntu中了。 # adb pull /data/Hello.class ./
2.Ubuntu要向手机发送一个文件
# sdb push test.txt /data 上面adb server已经启动了，这里就不需要再启动adb server了。
3.adb shell
若Ubuntu中执行了adb shell就相当于这个窗口做了一个串口控制台一样，成为了手机的串口终端了。可以在Ubuntu中另外打开一个窗口来和这个“串口终端”交互。此时Ubuntu和手机的交互就像Ubuntu中的两个窗口之间的交互一样。
三、adb排错
1.首先要确保手机端的adbd守护进程和Ubuntu中的adb server都正常运行起来了。
2.Ubuntu中可以重启adb服务试试：adb kill-server 然后 adb start-server
adb --help:
255|shell@xxxx:/vendor/lib/hw # adb --help Android Debug Bridge version 1.0.32 -a - directs adb to listen on all interfaces for a connection -d - directs command to the only connected USB device returns an error if more than one USB device is present. -e - directs command to the only running emulator. returns an error if more than one emulator is running. -s <specific device> - directs command to the device or emulator with the given serial number or qualifier. Overrides ANDROID_SERIAL environment variable. -p <product name or path> - simple product name like 'sooner', or a relative/absolute path to a product out directory like 'out/target/product/sooner'. If -p is not specified, the ANDROID_PRODUCT_OUT environment variable is used, which must be an absolute path. -H - Name of adb server host (default: localhost) -P - Port of adb server (default: 5037) devices [-l] - list all connected devices ('-l' will also list device qualifiers) connect <host>[:<port>] - connect to a device via TCP/IP Port 5555 is used by default if no port number is specified. disconnect [<host>[:<port>]] - disconnect from a TCP/IP device. Port 5555 is used by default if no port number is specified. Using this command with no additional arguments will disconnect from all connected TCP/IP devices. device commands: adb push [-p] <local> <remote> - copy file/dir to device ('-p' to display the transfer progress) adb pull [-p] [-a] <remote> [<local>] - copy file/dir from device ('-p' to display the transfer progress) ('-a' means copy timestamp and mode) adb sync [ <directory> ] - copy host->device only if changed (-l means list but don't copy) (see 'adb help all') adb shell - run remote shell interactively adb shell <command> - run remote shell command adb emu <command> - run emulator console command adb logcat [ <filter-spec> ] - View device log adb forward --list - list all forward socket connections. the format is a list of lines with the following format: <serial> " " <local> " " <remote> " " adb forward <local> <remote> - forward socket connections forward specs are one of: tcp:<port> localabstract:<unix domain socket name> localreserved:<unix domain socket name> localfilesystem:<unix domain socket name> dev:<character device name> jdwp:<process pid> (remote only) adb forward --no-rebind <local> <remote> - same as 'adb forward <local> <remote>' but fails if <local> is already forwarded adb forward --remove <local> - remove a specific forward socket connection adb forward --remove-all - remove all forward socket connections adb reverse --list - list all reverse socket connections from device adb reverse <remote> <local> - reverse socket connections reverse specs are one of: tcp:<port> localabstract:<unix domain socket name> localreserved:<unix domain socket name> localfilesystem:<unix domain socket name> adb reverse --norebind <remote> <local> - same as 'adb reverse <remote> <local>' but fails if <remote> is already reversed. adb reverse --remove <remote> - remove a specific reversed socket connection adb reverse --remove-all - remove all reversed socket connections from device adb jdwp - list PIDs of processes hosting a JDWP transport adb install [-lrtsd] <file> adb install-multiple [-lrtsdp] <file...> - push this package file to the device and install it (-l: forward lock application) (-r: replace existing application) (-t: allow test packages) (-s: install application on sdcard) (-d: allow version code downgrade) (-p: partial application install) adb uninstall [-k] <package> - remove this app package from the device ('-k' means keep the data and cache directories) adb bugreport - return all information from the device that should be included in a bug report. adb backup [-f <file>] [-apk|-noapk] [-obb|-noobb] [-shared|-noshared] [-all] [-system|-nosystem] [<packages...>] - write an archive of the device's data to <file>. If no -f option is supplied then the data is written to "backup.ab" in the current directory. (-apk|-noapk enable/disable backup of the .apks themselves in the archive; the default is noapk.) (-obb|-noobb enable/disable backup of any installed apk expansion (aka .obb) files associated with each application; the default is noobb.) (-shared|-noshared enable/disable backup of the device's shared storage / SD card contents; the default is noshared.) (-all means to back up all installed applications) (-system|-nosystem toggles whether -all automatically includes system applications; the default is to include system apps) (<packages...> is the list of applications to be backed up. If the -all or -shared flags are passed, then the package list is optional. Applications explicitly given on the command line will be included even if -nosystem would ordinarily cause them to be omitted.) adb restore <file> - restore device contents from the <file> backup archive adb disable-verity - disable dm-verity checking on USERDEBUG builds adb keygen <file> - generate adb public/private key. The private key is stored in <file>, and the public key is stored in <file>.pub. Any existing files are overwritten. adb help - show this help message adb version - show version num scripting: adb wait-for-device - block until device is online adb start-server - ensure that there is a server running adb kill-server - kill the server if it is running adb get-state - prints: offline | bootloader | device adb get-serialno - prints: <serial-number> adb get-devpath - prints: <device-path> adb status-window - continuously print device status for a specified device adb remount - remounts the /system and /vendor (if present) partitions on the device read-write adb reboot [bootloader|recovery] - reboots the device, optionally into the bootloader or recovery program adb reboot-bootloader - reboots the device into the bootloader adb root - restarts the adbd daemon with root permissions adb usb - restarts the adbd daemon listening on USB adb tcpip <port> - restarts the adbd daemon listening on TCP on the specified port networking: adb ppp <tty> [parameters] - Run PPP over USB. Note: you should not automatically start a PPP connection. <tty> refers to the tty for PPP stream. Eg. dev:/dev/omap_csmi_tty1 [parameters] - Eg. defaultroute debug dump local notty usepeerdns adb sync notes: adb sync [ <directory> ] <localdir> can be interpreted in several ways: - If <directory> is not specified, /system, /vendor (if present), and /data partitions will be updated. - If it is "system", "vendor" or "data", only the corresponding partition is updated. environmental variables: ADB_TRACE - Print debug information. A comma separated list of the following values or all, adb, sockets, packets, rwx, usb, sync, sysdeps, transport, jdwp ANDROID_SERIAL - The serial number to connect to. -s takes priority over this if given. ANDROID_LOG_TAGS - When used with the logcat option, only these debug tags are printed.