hadoop中 Hadoop DistCp的api使用是什么呢？

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[root@node105 ~]# hadoop distcp
usage: distcp OPTIONS [source_path...] <target_path>
              OPTIONS
 -append                       Reuse existing data in target files and
                               append new data to them if possible
 -async                        Should distcp execution be blocking
 -atomic                       Commit all changes or none
 -bandwidth <arg>              Specify bandwidth per map in MB
 -blocksperchunk <arg>         If set to a positive value, fileswith more
                               blocks than this value will be split into
                               chunks of <blocksperchunk> blocks to be
                               transferred in parallel, and reassembled on
                               the destination. By default,
                               <blocksperchunk> is 0 and the files will be
                               transmitted in their entirety without
                               splitting. This switch is only applicable
                               when the source file system implements
                               getBlockLocations method and the target
                               file system implements concat method
 -copybuffersize <arg>         Size of the copy buffer to use. By default
                               <copybuffersize> is 8192B.
 -delete                       Delete from target, files missing in source
 -diff <arg>                   Use snapshot diff report to identify the
                               difference between source and target
 -f <arg>                      List of files that need to be copied
 -filelimit <arg>              (Deprecated!) Limit number of files copied
                               to <= n
 -filters <arg>                The path to a file containing a list of
                               strings for paths to be excluded from the
                               copy.
 -i                            Ignore failures during copy
 -log <arg>                    Folder on DFS where distcp execution logs
                               are saved
 -m <arg>                      Max number of concurrent maps to use for
                               copy
 -mapredSslConf <arg>          Configuration for ssl config file, to use
                               with hftps://. Must be in the classpath.
 -numListstatusThreads <arg>   Number of threads to use for building file
                               listing (max 40).
 -overwrite                    Choose to overwrite target files
                               unconditionally, even if they exist.
 -p <arg>                      preserve status (rbugpcaxt)(replication,
                               block-size, user, group, permission,
                               checksum-type, ACL, XATTR, timestamps). If
                               -p is specified with no <arg>, then
                               preserves replication, block size, user,
                               group, permission, checksum type and
                               timestamps. raw.* xattrs are preserved when
                               both the source and destination paths are
                               in the /.reserved/raw hierarchy (HDFS
                               only). raw.* xattrpreservation is
                               independent of the -p flag. Refer to the
                               DistCp documentation for more details.
 -rdiff <arg>                  Use target snapshot diff report to identify
                               changes made on target
 -sizelimit <arg>              (Deprecated!) Limit number of files copied
                               to <= n bytes
 -skipcrccheck                 Whether to skip CRC checks between source
                               and target paths.
 -strategy <arg>               Copy strategy to use. Default is dividing
                               work based on file sizes
 -tmp <arg>                    Intermediate work path to be used for
                               atomic commit
 -update                       Update target, copying only missingfiles or
                               directories