hadoop shell命令介绍

Hadoop 文件系统shell使用命令介绍，基本上所有的命令与linux命令相差不大，下面为我的hadoop系统文件夹
查看命令：hadoop fs -ls /home/hadoop/
drwxr-xr-x - hadoop supergroup 0 2013-11-30 17:51 /home/hadoop/dir
drwxr-xr-x - hadoop supergroup 0 2013-11-30 17:48 /home/hadoop/input
-rw-r–r– 1 hadoop supergroup 64 2013-11-30 17:50 /home/hadoop/ouput
drwxr-xr-x - hadoop supergroup 0 2013-11-29 22:50 /home/hadoop/output
drwxr-xr-x - hadoop supergroup 0 2013-11-29 22:50 /home/hadoop/tmp

查看所有命令帮助：hadoop fs –help

cat
Usage: hadoop fs -cat URI [URI …]
查看fs文件内容
例子:
hadoop fs -cat /home/hadoop/input/content.txt
Returns 0 on success and -1 on error.

chgrp
Usage: hadoop fs -chgrp [-R] GROUP URI [URI …]
Change group association of files. With -R, make the change recursively through the directory structure. The user must be the owner of files, or else a super-user. Additional information is in the Permissions User Guide.

chmod
Usage: hadoop fs -chmod [-R] <MODE[,MODE]… | OCTALMODE> URI [URI …]
Change the permissions of files. With -R, make the change recursively through the directory structure. The user must be the owner of the file, or else a super-user. Additional information is in the Permissions User Guide.

chown
Usage: hadoop fs -chown [-R] [OWNER][:[GROUP]] URI [URI ]
Change the owner of files. With -R, make the change recursively through the directory structure. The user must be a super-user. Additional information is in the Permissions User Guide.

copyFromLocal
Usage: hadoop fs -copyFromLocal URI
例子：
hadoop fs -copyFromLocal /home/hadoop/address /home/hadoop/input
Similar to put command, except that the source is restricted to a local file reference.

copyToLocal
Usage: hadoop fs -copyToLocal [-ignorecrc] [-crc] URI
例子：
hadoop fs -copyToLocal /home/hadoop/input/content.txt /home/hadoop/mylocal
Similar to get command, except that the destination is restricted to a local file reference.

cp
Usage: hadoop fs -cp URI [URI …]
Copy files from source to destination. This command allows multiple sources as well in which case the destination must be a directory.
例子:
hadoop fs -cp /home/hadoop/input/content.txt /home/hadoop/ouput
hadoop fs -cp /home/hadoop/input/address /home/hadoop/ouput /home/hadoop/dir
Exit Code:
Returns 0 on success and -1 on error.

du
Usage: hadoop fs -du URI [URI …]
Displays aggregate length of files contained in the directory or the length of a file in case its just a file.
例子:
hadoop fs -du /home/hadoop/dir /home/hadoop/input
输出结果：
Found 2 items
65 hdfs://localhost:9000/home/hadoop/dir/address
64 hdfs://localhost:9000/home/hadoop/dir/ouput
Found 2 items
65 hdfs://localhost:9000/home/hadoop/input/address
64 hdfs://localhost:9000/home/hadoop/input/content.txt

Exit Code:
Returns 0 on success and -1 on error.

dus
Usage: hadoop fs -dus
例子：
hadoop fs -dus /home/hadoop/dir

输出：hdfs://localhost:9000/home/hadoop/dir 129
Displays a summary of file lengths.

expunge 手动清除fs回收站
Usage: hadoop fs -expunge
Empty the Trash. Refer to HDFS Design for more information on Trash feature.

get
Usage: hadoop fs -get [-ignorecrc] [-crc]
Copy files to the local file system. Files that fail the CRC check may be copied with the -ignorecrc option. Files and CRCs may be copied using the -crc option.
例子:
hadoop fs -get /home/hadoop/input/content.txt /home/hadoop/mylocal/
hadoop fs -get hdfs://nn.example.com/user/hadoop/file localfile
Exit Code:
Returns 0 on success and -1 on error.

getmerge
Usage: hadoop fs -getmerge [addnl]
Takes a source directory and a destination file as input and concatenates files in src into the destination local file. Optionally addnl can be set to enable adding a newline character at the end of each file.

ls
Usage: hadoop fs -ls
For a file returns stat on the file with the following format:
filename filesize modification_date modification_time permissions userid groupid
For a directory it returns list of its direct children as in unix. A directory is listed as:
dirname

modification_time modification_time permissions userid groupid
例子:
hadoop fs -ls /home/hadoop/input/ /home/hadoop/ouput/
输出：
Found 2 items
-rw-r–r– 1 hadoop supergroup 65 2013-11-30 17:48 /home/hadoop/input/address
-rw-r–r– 1 hadoop supergroup 64 2013-11-29 22:48 /home/hadoop/input/content.txt
Found 1 items
-rw-r–r– 1 hadoop supergroup 64 2013-11-30 17:50 /home/hadoop/ouput
Exit Code:
Returns 0 on success and -1 on error.

lsr
Usage: hadoop fs -lsr
例子：
hadoop fs -lsr /home/hadoop/input/ /home/hadoop/ouput/

输出：
-rw-r–r– 1 hadoop supergroup 65 2013-11-30 17:48 /home/hadoop/input/address
-rw-r–r– 1 hadoop supergroup 64 2013-11-29 22:48 /home/hadoop/input/content.txt
-rw-r–r– 1 hadoop supergroup 64 2013-11-30 17:50 /home/hadoop/ouput
Recursive version of ls. Similar to Unix ls -R.

mkdir
Usage: hadoop fs -mkdir
Takes path uri’s as argument and creates directories. The behavior is much like unix mkdir -p creating parent directories along the path.
例子:
hadoop fs -mkdir /home/hadoop/input/ /home/hadoop/ouput/
hadoop fs -mkdir hdfs://nn1.example.com/user/hadoop/dir hdfs://nn2.example.com/user/hadoop/dir
Exit Code:
Returns 0 on success and -1 on error.

movefromLocal
Usage: dfs -moveFromLocal
Displays a “not implemented” message.

mv
Usage: hadoop fs -mv URI [URI …]
Moves files from source to destination. This command allows multiple sources as well in which case the destination needs to be a directory. Moving files across filesystems is not permitted.
例子:
hadoop fs -mv /home/hadoop/input/lzw /home/hadoop/output
hadoop fs -mv hdfs://nn.example.com/file1 hdfs://nn.example.com/file2 hdfs://nn.example.com/file3 hdfs://nn.example.com/dir1
Exit Code:
Returns 0 on success and -1 on error.

put
Usage: hadoop fs -put …
Copy single src, or multiple srcs from local file system to the destination filesystem. Also reads input from stdin and writes to destination filesystem.
hadoop fs -put /home/hadoop/lzw /home/hadoop/input
hadoop fs -put /home/hadoop/lzw /home/hadoop/lzw1 /home/hadoop/input
hadoop fs -put localfile hdfs://nn.example.com/hadoop/hadoopfile
hadoop fs -put - hdfs://nn.example.com/hadoop/hadoopfile
Reads the input from stdin.

Exit Code:
Returns 0 on success and -1 on error.

rm 删除文件
Usage: hadoop fs -rm URI [URI …]
Delete files specified as args. Only deletes non empty directory and files. Refer to rmr for recursive deletes.
例子:
hadoop fs -rm /home/hadoop/output/lzw
Exit Code:
Returns 0 on success and -1 on error.

rmr 删除文件夹
Usage: hadoop fs -rmr URI [URI …]
Recursive version of delete.
例子:
hadoop fs -rmr /home/hadoop/output
hadoop fs -rmr hdfs://nn.example.com/user/hadoop/dir
Exit Code:
Returns 0 on success and -1 on error.

setrep
Usage: hadoop fs -setrep [-R]
Changes the replication factor of a file. -R option is for recursively increasing the replication factor of files within a directory.
例子:
hadoop fs -setrep -w 3 -R /user/hadoop/dir1
Exit Code:
Returns 0 on success and -1 on error.

stat
Usage: hadoop fs -stat URI [URI …]
Returns the stat information on the path.
例子:
hadoop fs -stat /home/hadoop/input
输出：
2013-11-30 16:00:27
Exit Code:
Returns 0 on success and -1 on error.

tail
Usage: hadoop fs -tail [-f] URI
Displays last kilobyte of the file to stdout. -f option can be used as in Unix.
例子:
hadoop fs -tail pathname
Exit Code:
Returns 0 on success and -1 on error.

test
Usage: hadoop fs -test -[ezd] URI
Options:
-e check to see if the file exists. Return 0 if true.
-z check to see if the file is zero length. Return 0 if true
-d check return 1 if the path is directory else return 0.
例子:
hadoop fs -test -d /home/hadoop/input
hadoop fs -test -e /home/hadoop/input
hadoop fs -test -z /home/hadoop/input

text 查看文件内容，跟cat基本相似
Usage: hadoop fs -text
例子：
hadoop fs -text /home/hadoop/input/address
输出：
addressID addressname
1 Beijing
2 Guangzhou
3 Shenzhen
4 Xian
Takes a source file and outputs the file in text format. The allowed formats are zip and TextRecordInputStream.

touchz 创建空文件
Usage: hadoop fs -touchz URI [URI …]
Create a file of zero length.
例子:
hadoop fs -touchz /home/hadoop/input/lzw
Exit Code:
Returns 0 on success and -1 on error.

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以上命令先记下来，在以后的用的过程中不会的再来翻阅。