• 2>&1的含义解释


    某次想将adb的help信息保存起来

    F:android系统AndroidTool_Release_v2.65in>adb >help.txt

    结果

    F:android系统AndroidTool_Release_v2.65in>adb >help.txt
    Android Debug Bridge version 1.0.31
    
     -a                            - directs adb to listen on all interfaces for a c
    onnection
     -d                            - directs command to the only connected USB devic
    e
                                     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 r
    unning.
     -s <specific device>          - directs command to the device or emulator with
    the given
                                     serial number or qualifier. Overrides ANDROID_S
    ERIAL
                                     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 devic
    es.
    
    device commands:
      adb push <local> <remote>    - copy file/dir to device
      adb pull <remote> [<local>]  - copy file/dir from device
      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 followin
    g 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 fail
    s
                                     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 jdwp                     - list PIDs of processes hosting a JDWP transport
    
      adb install [-l] [-r] [-s] [--algo <algorithm name> --key <hex-encoded key> --
    iv <hex-encoded iv>] <file>
                                   - push this package file to the device and instal
    l it
                                     ('-l' means forward-lock the app)
                                     ('-r' means reinstall the app, keeping its data
    )
                                     ('-s' means install on SD card instead of inter
    nal storage)
                                     ('--algo', '--key', and '--iv' mean the file is
     encrypted already)
      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 wr
    itten
                                     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 insta
    lled apk expansion
                                        (aka .obb) files associated with each applic
    ation; the default
                                        is noobb.)
                                     (-shared|-noshared enable/disable backup of the
     device's
                                        shared storage / SD card contents; the defau
    lt is noshared.)
                                     (-all means to back up all installed applicatio
    ns)
                                     (-system|-nosystem toggles whether -all automat
    ically includes
                                        system applications; the default is to inclu
    de system apps)
                                     (<packages...> is the list of applications to b
    e backed up.  If
                                        the -all or -shared flags are passed, then t
    he package
                                        list is optional.  Applications explicitly g
    iven on the
                                        command line will be included even if -nosys
    tem would
                                        ordinarily cause them to be omitted.)
    
      adb restore <file>           - restore device contents from the <file> backup
    archive
    
      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 specifie
    d device
      adb remount                  - remounts the /system partition on the device re
    ad-write
      adb reboot [bootloader|recovery] - reboots the device, optionally into the boo
    tloader 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 th
    e 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, both /system and /data partitions will be u
    pdated.
    
      - If it is "system" or "data", only the corresponding partition
        is updated.
    
    environmental variables:
      ADB_TRACE                    - Print debug information. A comma separated list
     of the following values
                                     1 or all, adb, sockets, packets, rwx, usb, sync
    , sysdeps, transport, jdwp
      ANDROID_SERIAL               - The serial number to connect to. -s takes prior
    ity over this if given.
      ANDROID_LOG_TAGS             - When used with the logcat option, only these de
    bug tags are printed.
    View Code

    help.txt是空的。。。

    那么我们怎么想在help.txt有输出呢

    F:android系统AndroidTool_Release_v2.65in>adb >help.txt 2>&1

    现在

    我们的help.txt中有

    Android Debug Bridge version 1.0.31
    
     -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 <local> <remote>    - copy file/dir to device
      adb pull <remote> [<local>]  - copy file/dir from device
      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 jdwp                     - list PIDs of processes hosting a JDWP transport
      adb install [-l] [-r] [-s] [--algo <algorithm name> --key <hex-encoded key> --iv <hex-encoded iv>] <file>
                                   - push this package file to the device and install it
                                     ('-l' means forward-lock the app)
                                     ('-r' means reinstall the app, keeping its data)
                                     ('-s' means install on SD card instead of internal storage)
                                     ('--algo', '--key', and '--iv' mean the file is encrypted already)
      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 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 partition 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, both /system and /data partitions will be updated.
    
      - If it is "system" or "data", only the corresponding partition
        is updated.
    
    environmental variables:
      ADB_TRACE                    - Print debug information. A comma separated list of the following values
                                     1 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.
    View Code

    关于2>&1的含义:将标准错误输出重定向到标准输出

    其他扩展阅读

    https://blog.csdn.net/zhaominpro/article/details/82630528

    https://yanbin.blog/linux-input-output-redirection/

  • 相关阅读:
    table拖动列宽
    解决 wm_concat函数 长度不够问题
    「Luogu」[JSOI2007]字符加密 解题报告
    Markdown数学符号
    「P5004」专心OI
    「CF242E」XOR on Segment 解题报告
    「CF86D」Powerful array 解题报告
    「USACO08JAN」电话线Telephone Lines 解题报告
    「Luogu P2015」二叉苹果树 解题报告
    「Luogu P3866」[TJOI2009]战争游戏 解题报告
  • 原文地址:https://www.cnblogs.com/libra13179/p/11326125.html
一二三 - 开发者的网上家园