二、HDFS命令行操作
基本命令
bin/hadoop fs 具体命令参数大全
[daxiong@hadoop hadoop-2.7.2]$ bin/hadoop fs
[-appendToFile <localsrc> ... <dst>]
[-cat [-ignoreCrc] <src> ...]
[-checksum <src> ...]
[-chgrp [-R] GROUP PATH...]
[-chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH...]
[-chown [-R] [OWNER][:[GROUP]] PATH...]
[-copyFromLocal [-f] [-p] <localsrc> ... <dst>]
[-copyToLocal [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
[-count [-q] <path> ...]
[-cp [-f] [-p] <src> ... <dst>]
[-createSnapshot <snapshotDir> [<snapshotName>]]
[-deleteSnapshot <snapshotDir> <snapshotName>]
[-df [-h] [<path> ...]]
[-du [-s] [-h] <path> ...]
[-expunge]
[-get [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
[-getfacl [-R] <path>]
[-getmerge [-nl] <src> <localdst>]
[-help [cmd ...]]
[-ls [-d] [-h] [-R] [<path> ...]]
[-mkdir [-p] <path> ...]
[-moveFromLocal <localsrc> ... <dst>]
[-moveToLocal <src> <localdst>]
[-mv <src> ... <dst>]
[-put [-f] [-p] <localsrc> ... <dst>]
[-renameSnapshot <snapshotDir> <oldName> <newName>]
[-rm [-f] [-r|-R] [-skipTrash] <src> ...]
[-rmdir [--ignore-fail-on-non-empty] <dir> ...]
[-setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>]]
[-setrep [-R] [-w] <rep> <path> ...]
[-stat [format] <path> ...]
[-tail [-f] <file>]
[-test -[defsz] <path>]
[-text [-ignoreCrc] <src> ...]
[-touchz <path> ...]
[-usage [cmd ...]]
常用命令实际操作
启动Hadoop集群（方便后续的测试）
启动HDFS集群 [daxiong@hadoop102 hadoop-2.7.2]$ sbin/start-dfs.sh 启动yarn集群 [daxiong@hadoop102 hadoop-2.7.2]$ sbin/start-yarn.sh-help：输出这个命令参数
#比如查看rm的用法 [daxiong@hadoop102 bin]$ ./hadoop fs -help rm -rm [-f] [-r|-R] [-skipTrash] <src> ... : Delete all files that match the specified file pattern. Equivalent to the Unix command "rm <src>" -skipTrash option bypasses trash, if enabled, and immediately deletes <src> -f If the file does not exist, do not display a diagnostic message or modify the exit status to reflect an error. -[rR] Recursively deletes directories-ls: 显示目录信息
[daxiong@hadoop102 bin]$ ./hadoop fs -ls / Found 1 items drwxrwx--- - daxiong supergroup 0 2018-04-08 22:49 /tmp-mkdir：在hdfs上创建目录
#创建一个 /daxiong文件夹 [daxiong@hadoop102 bin]$ ./hadoop fs -mkdir /daxiong #创建一个 /daxiong/haha/da/da/da文件夹，需要加上 -p 参数 [daxiong@hadoop102 bin]$ ./hadoop fs -mkdir -p /daxiong/haha/da/da/da #查看是否创建成功 [daxiong@hadoop102 bin]$ ./hadoop fs -ls / Found 1 items drwxr-xr-x - daxiong supergroup 0 2018-04-10 20:09 /daxiong #递归查看是否创建成功 [daxiong@hadoop102 bin]$ ./hadoop fs -ls -R / drwxr-xr-x - daxiong supergroup 0 2018-04-10 20:51 /daxiong drwxr-xr-x - daxiong supergroup 0 2018-04-10 20:51 /daxiong/haha drwxr-xr-x - daxiong supergroup 0 2018-04-10 20:54 /daxiong/haha/da drwxr-xr-x - daxiong supergroup 0 2018-04-10 20:54 /daxiong/haha/da/da drwxr-xr-x - daxiong supergroup 0 2018-04-10 20:54 /daxiong/haha/da/da/da-moveFromLocal从本地剪切粘贴到hdfs
-appendToFile ：追加一个文件到已经存在的文件末尾
-cat ：显示文件内容
-tail：显示一个文件的末尾
-chgrp 、-chmod、-chown：linux文件系统中的用法一样，修改文件所属权限
-copyFromLocal：从本地文件系统中拷贝文件到hdfs路径去
-copyToLocal：从hdfs拷贝到本地
-cp ：从hdfs的一个路径拷贝到hdfs的另一个路径
-mv：在hdfs目录中移动文件
-get：等同于copyToLocal，就是从hdfs下载文件到本地
-getmerge ：合并下载多个文件，比如hdfs的目录 /aaa/下有多个文件:log.1, log.2,log.3,…
-put：等同于copyFromLocal
#把本机/opt/moudle/hadoop-2.7.2/daxiong.txt 文件放到HDFS上的/daxiong文件夹下 [daxiong@hadoop102 bin]$ ./hadoop fs -put /opt/moudle/hadoop-2.7.2/daxiong.txt /daxiong-rm：删除文件或文件夹
#强制删除 /tmp文件夹 [daxiong@hadoop102 bin]$ ./hadoop fs -rm -r /tmp 18/04/10 20:08:03 INFO fs.TrashPolicyDefault: Namenode trash configuration: Deletion interval = 0 minutes, Em ptier interval = 0 minutes.Deleted /tmp-rmdir：删除空目录
-df ：统计文件系统的可用空间信息
-du统计文件夹的大小信息
[daxiong@hadoop102 bin]$ ./hadoop fs -df Filesystem Size Used Available Use% hdfs://hadoop101:8020 31304097792 114688 17920761856 0%
-setrep：设置hdfs中文件的副本数量