start-all.cmd
setlocal enabledelayedexpansion
//@rem is the main comment
@rem Start all hadoop daemons. Run this on master node.
//echo is the output text
echo This script is Deprecated. Instead use start-dfs.cmd and start-yarn.cmd
//%~dp0 indicates the directory where the current batch is located
if not defined HADOOP_BIN_PATH (
set HADOOP_BIN_PATH=%~dp0
)
//To determine whether the path ends with \, %xxx% represents the environment variable. %xx:~-1%, take the last character of the xx string. %xx:~0-1%, take the 1st to the penultimate character of the xx string.
if "%HADOOP_BIN_PATH:~-1%" == "\" (
set HADOOP_BIN_PATH=%HADOOP_BIN_PATH:~0,-1%
)
//The same level libexec directory of the bin directory
set DEFAULT_LIBEXEC_DIR=%HADOOP_BIN_PATH%\..\libexec
if not defined HADOOP_LIBEXEC_DIR (
set HADOOP_LIBEXEC_DIR=%DEFAULT_LIBEXEC_DIR%
)
call hadoop-config.cmd
call %HADOOP_LIBEXEC_DIR%\hadoop-config.cmd %*
if "%1" == "--config" (
shift
shift
)
Call start-dfs.cmd --config %HADOOP_CONF_DIR%. %HADOOP_CONF_DIR% is a variable defined in hadoop-config.cmd.
@rem start hdfs daemons if hdfs is present
if exist %HADOOP_HDFS_HOME%\sbin\start-dfs.cmd (
call %HADOOP_HDFS_HOME%\sbin\start-dfs.cmd --config %HADOOP_CONF_DIR%
)
调用start-yarn.cmd --config %HADOOP_CONF_DIR%。%HADOOP_CONF_DIR%是hadoop-config.cmd中定义的变量。
@rem start yarn daemons if yarn is present
if exist %HADOOP_YARN_HOME%\sbin\start-yarn.cmd (
call %HADOOP_YARN_HOME%\sbin\start-yarn.cmd --config %HADOOP_CONF_DIR%
)
endlocal
-----------------
hadoop-config.cmd
//设置环境变量
if not defined HADOOP_COMMON_DIR (
set HADOOP_COMMON_DIR=share\hadoop\common
)
if not defined HADOOP_COMMON_LIB_JARS_DIR (
set HADOOP_COMMON_LIB_JARS_DIR=share\hadoop\common\lib
)
if not defined HADOOP_COMMON_LIB_NATIVE_DIR (
set HADOOP_COMMON_LIB_NATIVE_DIR=lib\native
)
if not defined HDFS_DIR (
set HDFS_DIR=share\hadoop\hdfs
)
if not defined HDFS_LIB_JARS_DIR (
set HDFS_LIB_JARS_DIR=share\hadoop\hdfs\lib
)
if not defined YARN_DIR (
set YARN_DIR=share\hadoop\yarn
)
if not defined YARN_LIB_JARS_DIR (
set YARN_LIB_JARS_DIR=share\hadoop\yarn\lib
)
if not defined MAPRED_DIR (
set MAPRED_DIR=share\hadoop\mapreduce
)
if not defined MAPRED_LIB_JARS_DIR (
set MAPRED_LIB_JARS_DIR=share\hadoop\mapreduce\lib
)
//设置HADOOP_HOME=当前目录就是d:\hadoop2.3.7\libexec\目录
@rem the root of the Hadoop installation
set HADOOP_HOME=%~dp0
//FOR 参数 %%变量名 IN (相关文件或命令) DO 执行的命令
for %%i in (%HADOOP_HOME%.) do (
set HADOOP_HOME=%%~dpi
)
//执行上面for后就变成了d:\hadoop2.3.7\，下面是去掉最后一个\
if "%HADOOP_HOME:~-1%" == "\" (
set HADOOP_HOME=%HADOOP_HOME:~0,-1%
)
//如果hadoop-common-*.jar不存在就直接报错
if not exist %HADOOP_HOME%\share\hadoop\common\hadoop-common-*.jar (
@echo +================================================================+
@echo ^| Error: HADOOP_HOME is not set correctly ^|
@echo +----------------------------------------------------------------+
@echo ^| Please set your HADOOP_HOME variable to the absolute path of ^|
@echo ^| the directory that contains the hadoop distribution ^|
@echo +================================================================+
exit /b 1
)
//设置HADOOP_CONF_DIR
if not defined HADOOP_CONF_DIR (
set HADOOP_CONF_DIR=%HADOOP_HOME%\etc\hadoop
)
@rem
@rem Allow alternate conf dir location.
@rem
//判断--config是不是第二个参数，如果是就把第三个参数指定给HADOOP_CONF_DIR.shift,shift后再计算参数时排除当前这两个。
if "%1" == "--config" (
set HADOOP_CONF_DIR=%2
shift
shift
)
@rem
@rem Set log level. Default to INFO.
@rem
//判断-loglevel是不是第二个参数，如果是就把第三个参数指定给HADOOP_CONF_DIR
if "%1" == "--loglevel" (
set HADOOP_LOGLEVEL=%2
shift
shift
)
@rem
@rem check to see it is specified whether to use the slaves or the
@rem masters file
@rem
//判断--hosts是不是第二个参数，如果是就把第三个参数指定给HADOOP_CONF_DIR
if "%1" == "--hosts" (
set HADOOP_SLAVES=%HADOOP_CONF_DIR%\%2
shift
shift
)
调用hadoop-env.cmd
if exist %HADOOP_CONF_DIR%\hadoop-env.cmd (
call %HADOOP_CONF_DIR%\hadoop-env.cmd
)
@rem
@rem setup java environment variables
@rem
//没设置java_home直接报错
if not defined JAVA_HOME (
echo Error: JAVA_HOME is not set.
goto :eof
)
//如果%JAVA_HOME%\bin\java.exe不错在，要更新hadoop-env.cmd。因为hadoop-env.cmd也可以设置java_home
if not exist %JAVA_HOME%\bin\java.exe (
echo Error: JAVA_HOME is incorrectly set.
echo Please update %HADOOP_HOME%\conf\hadoop-env.cmd
goto :eof
)
设置JAVA=java.exe
set JAVA=%JAVA_HOME%\bin\java
@rem some Java parameters
设置java堆最大为1000M
set JAVA_HEAP_MAX=-Xmx1000m
@rem
@rem check envvars which might override default args
@rem
//如果有，则覆盖上面java的堆参数。
if defined HADOOP_HEAPSIZE (
set JAVA_HEAP_MAX=-Xmx%HADOOP_HEAPSIZE%m
)
@rem
@rem CLASSPATH initially contains %HADOOP_CONF_DIR%
@rem
设置CLASSPATH
set CLASSPATH=%HADOOP_CONF_DIR%
if not defined HADOOP_COMMON_HOME (
if exist %HADOOP_HOME%\share\hadoop\common (
set HADOOP_COMMON_HOME=%HADOOP_HOME%
)
)
@rem
@rem for releases, add core hadoop jar & webapps to CLASSPATH
@rem
附加CLASSPATH
if exist %HADOOP_COMMON_HOME%\%HADOOP_COMMON_DIR%\webapps (
set CLASSPATH=!CLASSPATH!;%HADOOP_COMMON_HOME%\%HADOOP_COMMON_DIR%
)
附加CLASSPATH
if exist %HADOOP_COMMON_HOME%\%HADOOP_COMMON_LIB_JARS_DIR% (
set CLASSPATH=!CLASSPATH!;%HADOOP_COMMON_HOME%\%HADOOP_COMMON_LIB_JARS_DIR%\*
)
附加CLASSPATH
set CLASSPATH=!CLASSPATH!;%HADOOP_COMMON_HOME%\%HADOOP_COMMON_DIR%\*
@rem
@rem default log directory % file
@rem
//定义日志目录
if not defined HADOOP_LOG_DIR (
set HADOOP_LOG_DIR=%HADOOP_HOME%\logs
)
//定义日志文件名
if not defined HADOOP_LOGFILE (
set HADOOP_LOGFILE=hadoop.log
)
//定义日志输出级别
if not defined HADOOP_LOGLEVEL (
set HADOOP_LOGLEVEL=INFO
)
if not defined HADOOP_ROOT_LOGGER (
set HADOOP_ROOT_LOGGER=%HADOOP_LOGLEVEL%,console
)
@rem
@rem default policy file for service-level authorization
@rem
设置安全权限相关内容
if not defined HADOOP_POLICYFILE (
set HADOOP_POLICYFILE=hadoop-policy.xml
)
@rem
@rem Determine the JAVA_PLATFORM
@rem
%%A代表in里面的个每个字符串（用空格区分）。设置JAVA_PLATFORM执行命令，%JAVA%就是xxx/java.exe，后面跟着java的参数，猜测是用这个执行命令来启动hadoop的。
for /f "delims=" %%A in ('%JAVA% -Xmx32m %HADOOP_JAVA_PLATFORM_OPTS% -classpath "%CLASSPATH%" org.apache.hadoop.util.PlatformName') do set JAVA_PLATFORM=%%A
@rem replace space with underscore
set JAVA_PLATFORM=%JAVA_PLATFORM: =_%
@rem
@rem setup 'java.library.path' for native hadoop code if necessary
@rem
设置java类库路径
@rem Check if we're running hadoop directly from the build
set JAVA_LIBRARY_PATH=
if exist %HADOOP_COMMON_HOME%\target\bin (
set JAVA_LIBRARY_PATH=%HADOOP_COMMON_HOME%\target\bin
)
@rem For the distro case, check the bin folder
if exist %HADOOP_COMMON_HOME%\bin (
set JAVA_LIBRARY_PATH=%JAVA_LIBRARY_PATH%;%HADOOP_COMMON_HOME%\bin
)
@rem
@rem setup a default TOOL_PATH
@rem
设置javatool路径
set TOOL_PATH=%HADOOP_HOME%\share\hadoop\tools\lib\*
定义hadoop的选项加上日志相关参数
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.log.dir=%HADOOP_LOG_DIR%
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.log.file=%HADOOP_LOGFILE%
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.home.dir=%HADOOP_HOME%
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.id.str=%HADOOP_IDENT_STRING%
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.root.logger=%HADOOP_ROOT_LOGGER%
定义hadoop的选项加上java类库
if defined JAVA_LIBRARY_PATH (
set HADOOP_OPTS=%HADOOP_OPTS% -Djava.library.path=%JAVA_LIBRARY_PATH%
)
定义hadoop的选项加上策略
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.policy.file=%HADOOP_POLICYFILE%
@rem
@rem Disable ipv6 as it can cause issues
@rem
用ipv4
set HADOOP_OPTS=%HADOOP_OPTS% -Djava.net.preferIPv4Stack=true
@rem
@rem put hdfs in classpath if present
@rem
if not defined HADOOP_HDFS_HOME (
if exist %HADOOP_HOME%\%HDFS_DIR% (
set HADOOP_HDFS_HOME=%HADOOP_HOME%
)
)
设置CLASSPATH
if exist %HADOOP_HDFS_HOME%\%HDFS_DIR%\webapps (
set CLASSPATH=!CLASSPATH!;%HADOOP_HDFS_HOME%\%HDFS_DIR%
)
if exist %HADOOP_HDFS_HOME%\%HDFS_LIB_JARS_DIR% (
set CLASSPATH=!CLASSPATH!;%HADOOP_HDFS_HOME%\%HDFS_LIB_JARS_DIR%\*
)
设置CLASSPATH
set CLASSPATH=!CLASSPATH!;%HADOOP_HDFS_HOME%\%HDFS_DIR%\*
@rem
@rem put yarn in classpath if present
@rem
if not defined HADOOP_YARN_HOME (
if exist %HADOOP_HOME%\%YARN_DIR% (
set HADOOP_YARN_HOME=%HADOOP_HOME%
)
)
if exist %HADOOP_YARN_HOME%\%YARN_DIR%\webapps (
set CLASSPATH=!CLASSPATH!;%HADOOP_YARN_HOME%\%YARN_DIR%
)
if exist %HADOOP_YARN_HOME%\%YARN_LIB_JARS_DIR% (
set CLASSPATH=!CLASSPATH!;%HADOOP_YARN_HOME%\%YARN_LIB_JARS_DIR%\*
)
set CLASSPATH=!CLASSPATH!;%HADOOP_YARN_HOME%\%YARN_DIR%\*
@rem
@rem put mapred in classpath if present AND different from YARN
@rem
if not defined HADOOP_MAPRED_HOME (
if exist %HADOOP_HOME%\%MAPRED_DIR% (
set HADOOP_MAPRED_HOME=%HADOOP_HOME%
)
)
这是classpath
if not "%HADOOP_MAPRED_HOME%\%MAPRED_DIR%" == "%HADOOP_YARN_HOME%\%YARN_DIR%" (
if exist %HADOOP_MAPRED_HOME%\%MAPRED_DIR%\webapps (
set CLASSPATH=!CLASSPATH!;%HADOOP_MAPRED_HOME%\%MAPRED_DIR%
)
if exist %HADOOP_MAPRED_HOME%\%MAPRED_LIB_JARS_DIR% (
set CLASSPATH=!CLASSPATH!;%HADOOP_MAPRED_HOME%\%MAPRED_LIB_JARS_DIR%\*
)
set CLASSPATH=!CLASSPATH!;%HADOOP_MAPRED_HOME%\%MAPRED_DIR%\*
)
@rem
@rem add user-specified CLASSPATH last
@rem
if defined HADOOP_CLASSPATH (
if not defined HADOOP_USE_CLIENT_CLASSLOADER (
if defined HADOOP_USER_CLASSPATH_FIRST (
set CLASSPATH=%HADOOP_CLASSPATH%;%CLASSPATH%;
) else (
set CLASSPATH=%CLASSPATH%;%HADOOP_CLASSPATH%;
)
)
)
:eof
-----------------------------
hadoop-env.cmd
设置java_home
set JAVA_HOME=%JAVA_HOME%
//容量调度器，当前版本没有。
if exist %HADOOP_HOME%\contrib\capacity-scheduler (
if not defined HADOOP_CLASSPATH (
//我们没有设置HADOOP_CLASSPATH，所以应该执行下面这句。
set HADOOP_CLASSPATH=%HADOOP_HOME%\contrib\capacity-scheduler\*.jar
) else (
set HADOOP_CLASSPATH=%HADOOP_CLASSPATH%;%HADOOP_HOME%\contrib\capacity-scheduler\*.jar
)
)
@rem The maximum amount of heap to use, in MB. Default is 1000.
@rem set HADOOP_HEAPSIZE=
@rem set HADOOP_NAMENODE_INIT_HEAPSIZE=""
@rem Extra Java runtime options. Empty by default.
@rem set HADOOP_OPTS=%HADOOP_OPTS% -Djava.net.preferIPv4Stack=true
@rem Command specific options appended to HADOOP_OPTS when specified
设置日志环境变量
if not defined HADOOP_SECURITY_LOGGER (
set HADOOP_SECURITY_LOGGER=INFO,RFAS
)
if not defined HDFS_AUDIT_LOGGER (
set HDFS_AUDIT_LOGGER=INFO,NullAppender
)
设置名称节点选项，安全日志，审计记录
set HADOOP_NAMENODE_OPTS=-Dhadoop.security.logger=%HADOOP_SECURITY_LOGGER% -Dhdfs.audit.logger=%HDFS_AUDIT_LOGGER% %HADOOP_NAMENODE_OPTS%
set HADOOP_DATANODE_OPTS=-Dhadoop.security.logger=ERROR,RFAS %HADOOP_DATANODE_OPTS%
set HADOOP_SECONDARYNAMENODE_OPTS=-Dhadoop.security.logger=%HADOOP_SECURITY_LOGGER% -Dhdfs.audit.logger=%HDFS_AUDIT_LOGGER% %HADOOP_SECONDARYNAMENODE_OPTS%
设置客户端选项
@rem The following applies to multiple commands (fs, dfs, fsck, distcp etc)
set HADOOP_CLIENT_OPTS=-Xmx512m %HADOOP_CLIENT_OPTS%
@rem set HADOOP_JAVA_PLATFORM_OPTS="-XX:-UsePerfData %HADOOP_JAVA_PLATFORM_OPTS%"
@rem On secure datanodes, user to run the datanode as after dropping privileges
set HADOOP_SECURE_DN_USER=%HADOOP_SECURE_DN_USER%
@rem Where log files are stored. %HADOOP_HOME%/logs by default.
@rem set HADOOP_LOG_DIR=%HADOOP_LOG_DIR%\%USERNAME%
@rem Where log files are stored in the secure data environment.
set HADOOP_SECURE_DN_LOG_DIR=%HADOOP_LOG_DIR%\%HADOOP_HDFS_USER%
@rem The directory where pid files are stored. /tmp by default.
@rem NOTE: this should be set to a directory that can only be written to by
@rem the user that will run the hadoop daemons. Otherwise there is the
@rem potential for a symlink attack.
set HADOOP_PID_DIR=%HADOOP_PID_DIR%
set HADOOP_SECURE_DN_PID_DIR=%HADOOP_PID_DIR%
@rem A string representing this instance of hadoop. %USERNAME% by default.
set HADOOP_IDENT_STRING=%USERNAME%
-----------------------
start-dfs.cmd
setlocal enabledelayedexpansion
同上HADOOP_BIN_PATH=${hadoop_install}\sbin
if not defined HADOOP_BIN_PATH (
set HADOOP_BIN_PATH=%~dp0
)
if "%HADOOP_BIN_PATH:~-1%" == "\" (
set HADOOP_BIN_PATH=%HADOOP_BIN_PATH:~0,-1%
)
同上
set DEFAULT_LIBEXEC_DIR=%HADOOP_BIN_PATH%\..\libexec
if not defined HADOOP_LIBEXEC_DIR (
set HADOOP_LIBEXEC_DIR=%DEFAULT_LIBEXEC_DIR%
)
同上，判断是否有自定义的config参数
call %HADOOP_LIBEXEC_DIR%\hdfs-config.cmd %*
if "%1" == "--config" (
shift
shift
)
windows下的命令，启动一个单独的窗口运行一个新程序。 "Apache Hadoop Distribution"窗口的标题。hadoop是一个可执行文件
start "Apache Hadoop Distribution" hadoop namenode
start "Apache Hadoop Distribution" hadoop datanode
endlocal
-----------------------
hdfs-config.cmd
同上
if not defined HADOOP_BIN_PATH (
set HADOOP_BIN_PATH=%~dp0
)
同上
if "%HADOOP_BIN_PATH:~-1%" == "\" (
set HADOOP_BIN_PATH=%HADOOP_BIN_PATH:~0,-1%
)
set DEFAULT_LIBEXEC_DIR=%HADOOP_BIN_PATH%\..\libexec
if not defined HADOOP_LIBEXEC_DIR (
set HADOOP_LIBEXEC_DIR=%DEFAULT_LIBEXEC_DIR%
)
if exist %HADOOP_LIBEXEC_DIR%\hadoop-config.cmd (
call %HADOOP_LIBEXEC_DIR%\hadoop-config.cmd %*
) else if exist %HADOOP_COMMON_HOME%\libexec\hadoop-config.cmd (
call %HADOOP_COMMON_HOME%\libexec\hadoop-config.cmd %*
) else if exist %HADOOP_HOME%\libexec\hadoop-config.cmd (
call %HADOOP_HOME%\libexec\hadoop-config.cmd %*
) else (
echo Hadoop common not found.
)
:eof
---------------------
hadoop.cmd
同上
if not defined HADOOP_BIN_PATH (
set HADOOP_BIN_PATH=%~dp0
)
if "%HADOOP_BIN_PATH:~-1%" == "\" (
set HADOOP_BIN_PATH=%HADOOP_BIN_PATH:~0,-1%
)
:updatepath是标签，在本配置文件的下方，先执行此段逻辑。
call :updatepath %HADOOP_BIN_PATH%
:main
setlocal enabledelayedexpansion
set DEFAULT_LIBEXEC_DIR=%HADOOP_BIN_PATH%\..\libexec
if not defined HADOOP_LIBEXEC_DIR (
set HADOOP_LIBEXEC_DIR=%DEFAULT_LIBEXEC_DIR%
)
call %HADOOP_LIBEXEC_DIR%\hadoop-config.cmd %*
判断第一个参数是否是--config，如果是则左移动两个参数。也就是不需要这个参数。
if "%1" == "--config" (
shift
shift
)
判断第一个参数是否是--loglevel，如果是则左移动两个参数。也就是不需要这个参数。
if "%1" == "--loglevel" (
shift
shift
)
//提取第一个参数
set hadoop-command=%1
if not defined hadoop-command (
goto print_usage
)
call :make_command_arguments %*
设置hdfs的hdfscommands命令集合
set hdfscommands=namenode secondarynamenode datanode dfs dfsadmin fsck balancer fetchdt oiv dfsgroups
循环%hdfscommands%里的命令，如果%hdfscommands%中的命令和hdfscommands中的一致，则hdfscommand=真。
for %%i in ( %hdfscommands% ) do (
if %hadoop-command% == %%i set hdfscommand=true
)
if defined hdfscommand (
@echo DEPRECATED: Use of this script to execute hdfs command is deprecated. 1>&2
@echo Instead use the hdfs command for it. 1>&2
if exist %HADOOP_HDFS_HOME%\bin\hdfs.cmd (
call %HADOOP_HDFS_HOME%\bin\hdfs.cmd %*
goto :eof
) else if exist %HADOOP_HOME%\bin\hdfs.cmd (
call %HADOOP_HOME%\bin\hdfs.cmd %*
goto :eof
) else (
echo HADOOP_HDFS_HOME not found!
goto :eof
)
)
设置mapred的mapredcommands命令集合
set mapredcommands=pipes job queue mrgroups mradmin jobtracker tasktracker
for %%i in ( %mapredcommands% ) do (
if %hadoop-command% == %%i set mapredcommand=true
)
if defined mapredcommand (
@echo DEPRECATED: Use of this script to execute mapred command is deprecated. 1>&2
@echo Instead use the mapred command for it. 1>&2
if exist %HADOOP_MAPRED_HOME%\bin\mapred.cmd (
call %HADOOP_MAPRED_HOME%\bin\mapred.cmd %*
goto :eof
) else if exist %HADOOP_HOME%\bin\mapred.cmd (
call %HADOOP_HOME%\bin\mapred.cmd %*
goto :eof
) else (
echo HADOOP_MAPRED_HOME not found!
goto :eof
)
)
if %hadoop-command% == classpath (
if not defined hadoop-command-arguments (
@rem No need to bother starting up a JVM for this simple case.
@echo %CLASSPATH%
exit /b
)
)
set corecommands=fs version jar checknative distcp daemonlog archive classpath credential key
for %%i in ( %corecommands% ) do (
if %hadoop-command% == %%i set corecommand=true
)
if defined corecommand (
call :%hadoop-command%
) else (
set CLASSPATH=%CLASSPATH%;%CD%
set CLASS=%hadoop-command%
)
set path=%PATH%;%HADOOP_BIN_PATH%
@rem Always respect HADOOP_OPTS and HADOOP_CLIENT_OPTS
set HADOOP_OPTS=%HADOOP_OPTS% %HADOOP_CLIENT_OPTS%
@rem make sure security appender is turned off
if not defined HADOOP_SECURITY_LOGGER (
set HADOOP_SECURITY_LOGGER=INFO,NullAppender
)
set HADOOP_OPTS=%HADOOP_OPTS% -Dhadoop.security.logger=%HADOOP_SECURITY_LOGGER%
call %JAVA% %JAVA_HEAP_MAX% %HADOOP_OPTS% -classpath %CLASSPATH% %CLASS% %hadoop-command-arguments%
exit /b %ERRORLEVEL%
:fs
set CLASS=org.apache.hadoop.fs.FsShell
goto :eof
:version
set CLASS=org.apache.hadoop.util.VersionInfo
goto :eof
:jar
if defined YARN_OPTS (
@echo WARNING: Use "yarn jar" to launch YARN applications. 1>&2
) else if defined YARN_CLIENT_OPTS (
@echo WARNING: Use "yarn jar" to launch YARN applications. 1>&2
)
set CLASS=org.apache.hadoop.util.RunJar
goto :eof
:checknative
set CLASS=org.apache.hadoop.util.NativeLibraryChecker
goto :eof
:distcp
set CLASS=org.apache.hadoop.tools.DistCp
set CLASSPATH=%CLASSPATH%;%TOOL_PATH%
goto :eof
:daemonlog
set CLASS=org.apache.hadoop.log.LogLevel
goto :eof
:archive
set CLASS=org.apache.hadoop.tools.HadoopArchives
set CLASSPATH=%CLASSPATH%;%TOOL_PATH%
goto :eof
:classpath
set CLASS=org.apache.hadoop.util.Classpath
goto :eof
:credential
set CLASS=org.apache.hadoop.security.alias.CredentialShell
goto :eof
:key
set CLASS=org.apache.hadoop.crypto.key.KeyShell
goto :eof
//%: =_%用_替换空格的意思。：是分割符。
:updatepath
set path_to_add=%*
set current_path_comparable=%path%
set current_path_comparable=%current_path_comparable: =_%
set current_path_comparable=%current_path_comparable:(=_%
set current_path_comparable=%current_path_comparable:)=_%
set path_to_add_comparable=%path_to_add%
set path_to_add_comparable=%path_to_add_comparable: =_%
set path_to_add_comparable=%path_to_add_comparable:(=_%
set path_to_add_comparable=%path_to_add_comparable:)=_%
for %%i in ( %current_path_comparable% ) do (
if /i "%%i" == "%path_to_add_comparable%" (
set path_to_add_exist=true
)
)
set system_path_comparable=
set path_to_add_comparable=
if not defined path_to_add_exist path=%path_to_add%;%path%
set path_to_add=
//退出脚本，直接到文件末尾
goto :eof
@rem This changes %1, %2 etc. Hence those cannot be used after calling this.
下面的标签是利用循环提取参数
:make_command_arguments
if "%1" == "--config" (
shift
shift
)
if "%1" == "--loglevel" (
shift
shift
)
if [%2] == [] goto :eof
shift
set _arguments=
循环开始
:MakeCmdArgsLoop
if [%1]==[] goto :EndLoop
if not defined _arguments (
set _arguments=%1
) else (
set _arguments=!_arguments! %1
)
shift
goto :MakeCmdArgsLoop 跳到循环开始
:EndLoop
将提取出的变量赋值给hadoop-command-arguments
set hadoop-command-arguments=%_arguments%
goto :eof
:print_usage
@echo Usage: hadoop [--config confdir] [--loglevel loglevel] COMMAND
@echo where COMMAND is one of:
@echo fs run a generic filesystem user client
@echo version print the version
@echo jar ^<jar^> run a jar file
@echo note: please use "yarn jar" to launch
@echo YARN applications, not this command.
@echo checknative [-a^|-h] check native hadoop and compression libraries availability
@echo distcp ^<srcurl^> ^<desturl^> copy file or directories recursively
@echo archive -archiveName NAME -p ^<parent path^> ^<src^>* ^<dest^> create a hadoop archive
@echo classpath prints the class path needed to get the
@echo Hadoop jar and the required libraries
@echo credential interact with credential providers
@echo key manage keys via the KeyProvider
@echo daemonlog get/set the log level for each daemon
@echo or
@echo CLASSNAME run the class named CLASSNAME
@echo.
@echo Most commands print help when invoked w/o parameters.
endlocal
-----------------------
批处理之字符串接取
@echo off set ifo=abcdefghijklmnopqrstuvwxyz0123456789 echo 原字符串（第二行为各字符的序号）： echo %ifo% echo 123456789012345678901234567890123456 echo 截取前5个字符： echo %ifo:~0,5% echo 截取最后5个字符： echo %ifo:~-5% echo 截取第一个到倒数第6个字符： echo %ifo:~0,-5% echo 从第4个字符开始，截取5个字符： echo %ifo:~3,5% echo 从倒数第14个字符开始，截取5个字符： echo %ifo:~-14,5% pause