hdfs shell

命令会自动读取该客户端下的hadoop-2.8.1/etc/hadoop/下的配置文件,来设置相关的参数.
配置文件的切块大小和存储的副本数量
上面两个参数应该配置在客户端机器的hadoop目录中的hdfs-site.xml中配置

<property>
<name>dfs.blocksize</name>
<value>64m</value>
</property>

<property>
<name>dfs.replication</name>
<value>2</value>
</property>

所有的命令都需要再前面加上hadoop fs,也可通过该命令看所有的操作.

Usage: hadoop fs [generic options]
        [-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] [-l] [-d] <localsrc> ... <dst>]
        [-copyToLocal [-f] [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
        [-count [-q] [-h] [-v] [-t [<storage type>]] [-u] [-x] <path> ...]
        [-cp [-f] [-p | -p[topax]] [-d] <src> ... <dst>]
        [-createSnapshot <snapshotDir> [<snapshotName>]]
        [-deleteSnapshot <snapshotDir> <snapshotName>]
        [-df [-h] [<path> ...]]
        [-du [-s] [-h] [-x] <path> ...]
        [-expunge]
        [-find <path> ... <expression> ...]
        [-get [-f] [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
        [-getfacl [-R] <path>]
        [-getfattr [-R] {-n name | -d} [-e en] <path>]
        [-getmerge [-nl] [-skip-empty-file] <src> <localdst>]
        [-help [cmd ...]]
        [-ls [-C] [-d] [-h] [-q] [-R] [-t] [-S] [-r] [-u] [<path> ...]]
        [-mkdir [-p] <path> ...]
        [-moveFromLocal <localsrc> ... <dst>]
        [-moveToLocal <src> <localdst>]
        [-mv <src> ... <dst>]
        [-put [-f] [-p] [-l] [-d] <localsrc> ... <dst>]
        [-renameSnapshot <snapshotDir> <oldName> <newName>]
        [-rm [-f] [-r|-R] [-skipTrash] [-safely] <src> ...]
        [-rmdir [--ignore-fail-on-non-empty] <dir> ...]
        [-setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>]]
        [-setfattr {-n name [-v value] | -x name} <path>]
        [-setrep [-R] [-w] <rep> <path> ...]
        [-stat [format] <path> ...]
        [-tail [-f] <file>]
        [-test -[defsz] <path>]
        [-text [-ignoreCrc] <src> ...]
        [-touchz <path> ...]
        [-truncate [-w] <length> <path> ...]
        [-usage [cmd ...]]

命令	描述
put	上传文件
get	下载文件
mkdir	创建文件夹
mv	移动,更名
mv	移动
cp	复制
rm	删除
cat/tail	查看
ls	列出文件夹内容

hdfs客户端的常用操作命令
1、上传文件到hdfs中 hadoop fs -put /本地文件 /aaa
2、下载文件到客户端本地磁盘 hadoop fs -get /hdfs中的路径 /本地磁盘目录
3、在hdfs中创建文件夹 hadoop fs -mkdir -p /aaa/xxx
4、移动hdfs中的文件（更名） hadoop fs -mv /hdfs的路径1 /hdfs的另一个路径2
5、复制hdfs中的文件到hdfs的另一个目录 hadoop fs -cp /hdfs路径_1 /hdfs路径_2
6、删除hdfs中的文件或文件夹 hadoop fs -rm -r /aaa
7、查看hdfs中的文本文件内容

hadoop fs -cat /demo.txt
hadoop fs -tail -f /demo.txt

8、查看hdfs中的文件夹内容 hadoop fs -ls /hdfs路径_1