HFDS命令行操作（开发重点）

1）基本语法

bin/hadoop fs 具体命令

2）参数大全

       [faded@faded102 hadoop-2.7.2]$ bin/hadoop fs

[-appendToFile ... ]         [-cat [-ignoreCrc] ...]         [-checksum ...]         [-chgrp [-R] GROUP PATH...]         [-chmod [-R] PATH...]         [-chown [-R] [OWNER][:[GROUP]] PATH...]         [-copyFromLocal [-f] [-p] ... ]         [-copyToLocal [-p] [-ignoreCrc] [-crc] ... ]         [-count [-q] ...]         [-cp [-f] [-p] ... ]         [-createSnapshot []]         [-deleteSnapshot ]         [-df [-h] [ ...]]         [-du [-s] [-h] ...]         [-expunge]         [-get [-p] [-ignoreCrc] [-crc] ... ]         [-getfacl [-R] ]         [-getmerge [-nl] ]         [-help [cmd ...]]         [-ls [-d] [-h] [-R] [ ...]]         [-mkdir [-p] ...]         [-moveFromLocal ... ]         [-moveToLocal ]         [-mv ... ]         [-put [-f] [-p] ... ]         [-renameSnapshot ]         [-rm [-f] [-r|-R] [-skipTrash] ...]         [-rmdir [--ignore-fail-on-non-empty] ...]         [-setfacl [-R] [{-b|-k} {-m|-x } ]|[--set ]]         [-setrep [-R] [-w] ...]         [-stat [format] ...]         [-tail [-f] ]         [-test -[defsz] ]         [-text [-ignoreCrc] ...]         [-touchz ...]         [-usage [cmd ...]]

3）常用命令实操

（0）启动Hadoop集群（方便后续的测试）

[faded@ faded 102 hadoop-2.7.2]$ sbin/start-dfs.sh

 [faded @ faded 103 hadoop-2.7.2]$ sbin/start-yarn.sh

（1）-help：输出这个命令参数

[faded @ faded 102 hadoop-2.7.2]$ hadoop fs -help rm

（2）-ls: 显示目录信息

[faded @ faded 102 hadoop-2.7.2]$ hadoop fs -ls /

（3）-mkdir：在hdfs上创建目录

[faded @ faded 102 hadoop-2.7.2]$ hadoop fs -mkdir -p /user/atguigu/test

（4）-moveFromLocal从本地剪切粘贴到hdfs

[atguigu@hadoop102 hadoop-2.7.2]$ touch jinlian.txt

[faded@faded 102 hadoop-2.7.2]$ hadoop fs  -moveFromLocal  ./jinlian.txt  /user/atguigu/test

（5）--appendToFile  ：追加一个文件到已经存在的文件末尾

[faded @ faded 102 hadoop-2.7.2]$ touch ximen.txt

[faded @ faded 102 hadoop-2.7.2]$ vi ximen.txt

输入

wo ai  jinlian

[faded@faded102 hadoop-2.7.2]$ hadoop fs -appendToFile ximen.txt /user/faded/test/jinlian.txt

（6）-cat ：显示文件内容

（7）-tail：显示一个文件的末尾

[faded@faded102 hadoop-2.7.2]$ hadoop fs -tail /user/faded/test/jinlian.txt

（8）-chgrp 、-chmod、-chown：linux文件系统中的用法一样，修改文件所属权限

[faded@faded102 hadoop-2.7.2]$ hadoop fs -chmod  666  /user/faded/test/jinlian.txt

[[email protected]]$ hadoop fs -chown atguigu:atguigu   /user/faded/test/jinlian.txt

（9）-copyFromLocal：从本地文件系统中拷贝文件到hdfs路径去

[faded@faded102 hadoop-2.7.2]$ hadoop fs -copyFromLocal README.txt /user/faded/test

（10）-copyToLocal：从hdfs拷贝到本地

[[email protected]]$ hadoop fs -copyToLocal /user/faded/test/jinlian.txt ./jinlian.txt

（11）-cp ：从hdfs的一个路径拷贝到hdfs的另一个路径

[faded@faded102 hadoop-2.7.2]$ hadoop fs -cp /user/faded/test/jinlian.txt /jinlian2.txt

（12）-mv：在hdfs目录中移动文件

[faded@hadoop102 hadoop-2.7.2]$ hadoop fs -mv /jinlian2.txt /user/faded/test/

（13）-get：等同于copyToLocal，就是从hdfs下载文件到本地

[faded@faded102 hadoop-2.7.2]$ hadoop fs -get /user/faded/test/jinlian2.txt ./

（14）-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,...

[faded@faded102 hadoop-2.7.2]$ hadoop fs -getmerge /user/faded/test/* ./zaiyiqi.txt

（15）-put：等同于copyFromLocal

[faded@faded102 hadoop-2.7.2]$ hadoop fs -put ./zaiyiqi.txt /user/faded/test/

（16）-rm：删除文件或文件夹

[atguigu@hadoop102 hadoop-2.7.2]$ hadoop fs -rm /user/atguigu/test/jinlian2.txt

（17）-rmdir：删除空目录

[faded@faded102 hadoop-2.7.2]$ hadoop fs -mkdir /test

[faded@faded102 hadoop-2.7.2]$ hadoop fs -rmdir /test

（18）-df ：统计文件系统的可用空间信息

[faded@faded102 hadoop-2.7.2]$ hadoop fs -df -h /

（19）-du统计文件夹的大小信息

[faded@faded102 hadoop-2.7.2]$ hadoop fs -du -s -h /user/faded/test

2.7 K  /user/faded/test

[faded@faded102 hadoop-2.7.2]$ hadoop fs -du  -h /user/faded/test

1.3 K  /user/faded/test/README.txt

15 K  /user/faded/test/jinlian.txt

1.4 K  /user/faded/test/zaiyiqi.txt

（20）-setrep：设置hdfs中文件的副本数量

[faded@faded102 hadoop-2.7.2]$ hadoop fs -setrep 2 /user/faded/test/jinlian.txt

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这里设置的副本数只是记录在namenode的元数据中，是否真的会有这么多副本，还得看datanode的数量。因为目前只有3台设备，最多也就3个副本，只有节点数的增加到10台时，副本数才能达到10。