hadoop - Hadoop集群中如何进行数据操作？

Question

如何在Hadoop 集群中读写文件：文件读写操作和 HDFS 命令是什么？

Answer 1

使用 hadoop 命令。

hadoop dfs  -copyToLocal [-ignoreCrc] [-crc] <src> <localdst>
this commads write the file to local machine

hadoop dfs -copyFromLocal <local-file-path> <Hdfs-location>
this command write file into hdfs

更多命令只需写

hadoop dfs -help

hadoop fs is the command to execute fs commands. The full syntax is: 

hadoop fs [-fs <local | file system URI>] [-conf <configuration file>]
[-D <property=value>] [-ls <path>] [-lsr <path>] [-du <path>]
[-dus <path>] [-mv <src> <dst>] [-cp <src> <dst>] [-rm [-skipTrash] <src>]
[-rmr [-skipTrash] <src>] [-put <localsrc> ... <dst>] [-copyFromLocal <localsrc> ... <dst>]
[-moveFromLocal <localsrc> ... <dst>] [-get [-ignoreCrc] [-crc] <src> <localdst>
[-getmerge <src> <localdst> [addnl]] [-cat <src>]
[-copyToLocal [-ignoreCrc] [-crc] <src> <localdst>] [-moveToLocal <src> <localdst>]
[-mkdir <path>] [-report] [-setrep [-R] [-w] <rep> <path/file>]
[-touchz <path>] [-test -[ezd] <path>] [-stat [format] <path>]
[-tail [-f] <path>] [-text <path>]
[-chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH...]
[-chown [-R] [OWNER][:[GROUP]] PATH...]
[-chgrp [-R] GROUP PATH...]
[-count[-q] <path>]
[-help [cmd]]