hadoop(五): shell命令

hdfs dfs

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• -cat URI : 查看文件内容

1. 1. hdfs dfs -cat hdfs dfs -cat hdfs://mycluster/user/root/rcc1
   2. hdfs dfs -cat file:///usr/hdp/2.4.2.0-258/hadoop/bin/rcc

• -ls <args>： 查文件列表

1. 返回格式：permissions number_of_replicas userid groupid filesize modification_date modification_time filename

   [root@hdp2 ~]# hdfs dfs -ls
   Found 4 items
   drwx------   - root hdfs          0 2016-09-01 21:00 .Trash
   drwxr-xr-x   - root hdfs          0 2016-08-12 12:29 .hiveJars
   -rw-r--r--   3 root hdfs        531 2016-09-01 12:53 mapred
   -rw-r--r--   3 root hdfs       1857 2016-09-01 12:44 rcc1

• -mkdir <paths>   ： 创建目录
1. The behavior is much like unix mkdir -p creating parent directories along the path

   [root@hdp2 ~]# hdfs dfs -ls
   Found 4 items
   drwx------   - root hdfs          0 2016-09-01 21:00 .Trash
   drwxr-xr-x   - root hdfs          0 2016-08-12 12:29 .hiveJars
   -rw-r--r--   3 root hdfs        531 2016-09-01 12:53 mapred
   -rw-r--r--   3 root hdfs       1857 2016-09-01 12:44 rcc1
   [root@hdp2 ~]# hdfs dfs -mkdir hdfs://mycluster/user/root/zhu
   [root@hdp2 ~]# hdfs dfs -ls
   Found 5 items
   drwx------   - root hdfs          0 2016-09-01 21:00 .Trash
   drwxr-xr-x   - root hdfs          0 2016-08-12 12:29 .hiveJars
   -rw-r--r--   3 root hdfs        531 2016-09-01 12:53 mapred
   -rw-r--r--   3 root hdfs       1857 2016-09-01 12:44 rcc1
   drwxr-xr-x   - root hdfs          0 2016-09-02 04:35 zhu

• -copyFromLocal <localsrc> URI： 上传文件，类似于put
• -put <localsrc> ... <dst>

[root@hdp2 ~]# hdfs dfs -ls /user/root/zhu
[root@hdp2 ~]# hdfs dfs -put /usr/zhu/a1.png /user/root/zhu
[root@hdp2 ~]# hdfs dfs -copyFormLocal /usr/zhu/a2.png /user/root/zhu
-copyFormLocal: Unknown command
[root@hdp2 ~]# hdfs dfs -copyFromLocal /usr/zhu/a2.png /user/root/zhu
[root@hdp2 ~]# hdfs dfs -ls /user/root/zhu
Found 2 items
-rw-r--r--   3 root hdfs      86908 2016-09-02 04:48 /user/root/zhu/a1.png
-rw-r--r--   3 root hdfs      55823 2016-09-02 04:49 /user/root/zhu/a2.png
[root@hdp2 ~]#

• -copyToLocal [-ignorecrc] [-crc] URI <localdst> : 下载到本地
• -get [-ignorecrc] [-crc] <src> <localdst>

  [root@hdp2 ~]# clear
  [root@hdp2 ~]# hdfs dfs -ls /user/root/zhu
  Found 2 items
  -rw-r--r--   3 root hdfs      86908 2016-09-02 04:48 /user/root/zhu/a1.png
  -rw-r--r--   3 root hdfs      55823 2016-09-02 04:49 /user/root/zhu/a2.png
  [root@hdp2 ~]# hdfs dfs -copyToLocal hdfs://mycluster/user/root/zhu/a1.png /usr/zhu/tmp
  [root@hdp2 ~]# hdfs dfs -get /usr/root/zhu/a2.png /usr/zhu/tmp
  get: `/usr/root/zhu/a2.png': No such file or directory
  [root@hdp2 ~]# hdfs dfs -get /user/root/zhu/a2.png /usr/zhu/tmp
  [root@hdp2 ~]# cd /usr/zhu/tmp
  [root@hdp2 tmp]# ll
  total 144
  -rw-r--r-- 1 root root 86908 Sep  2 04:54 a1.png
  -rw-r--r-- 1 root root 55823 Sep  2 04:55 a2.png
  [root@hdp2 tmp]# 

1.  

• -count [-q] <paths> :统计
1. The output columns with -count are: DIR_COUNT, FILE_COUNT, CONTENT_SIZE FILE_NAME
2. The output columns with -q are: QUOTA, REMAINING_QUATA, SPACE_QUOTA, REMAINING_SPACE_QUOTA

   [root@hdp2 tmp]# hdfs dfs -count /user/root/zhu
              1            2             142731 /user/root/zhu
   [root@hdp2 tmp]# hdfs dfs -count -q /user/root/zhu
           none             inf            none             inf            1            2             142731 /user/root/zhu
   [root@hdp2 tmp]# 

3.  

• -du [-s] [-h] URI [URI …]:  统计大小

1. The -s option will result in an aggregate summary of file lengths being displayed, rather than the individual file
2. The -h option will format file sizes in a "human-readable" fashion (e.g 64.0m instead of 67108864)

   [root@hdp2 tmp]# hdfs dfs -du -h /user/root/zhu
   84.9 K  /user/root/zhu/a1.png
   54.5 K  /user/root/zhu/a2.png
   [root@hdp2 tmp]# 

• -rm -r [-skipTrash] URI [URI …]

1. -r: Recursive version of delete

   [root@hdp2 tmp]# hdfs dfs -ls /user/root/zhu
   Found 1 items
   -rw-r--r--   3 root hdfs      86908 2016-09-02 05:03 /user/root/zhu/a1.png
   [root@hdp2 tmp]# hdfs dfs -rm -r /user/root/zhu
   16/09/02 05:04:29 INFO fs.TrashPolicyDefault: Namenode trash configuration: Deletion interval = 360 minutes, Emptier interval = 0 minutes.
   Moved: 'hdfs://mycluster/user/root/zhu' to trash at: hdfs://mycluster/user/root/.Trash/Current
   [root@hdp2 tmp]# hdfs dfs -ls /user/root/zhu
   ls: `/user/root/zhu': No such file or directory
   [root@hdp2 tmp]# 

• -touchz URI [URI …]

1. Create a file of zero length

   [root@hdp2 tmp]# hdfs dfs -ls
   Found 4 items
   drwx------   - root hdfs          0 2016-09-02 05:02 .Trash
   drwxr-xr-x   - root hdfs          0 2016-08-12 12:29 .hiveJars
   -rw-r--r--   3 root hdfs        531 2016-09-01 12:53 mapred
   -rw-r--r--   3 root hdfs       1857 2016-09-01 12:44 rcc1
   [root@hdp2 tmp]# hdfs dfs -touchz a.txt
   [root@hdp2 tmp]# hdfs dfs -ls
   Found 5 items
   drwx------   - root hdfs          0 2016-09-02 05:02 .Trash
   drwxr-xr-x   - root hdfs          0 2016-08-12 12:29 .hiveJars
   -rw-r--r--   3 root hdfs          0 2016-09-02 05:08 a.txt
   -rw-r--r--   3 root hdfs        531 2016-09-01 12:53 mapred
   -rw-r--r--   3 root hdfs       1857 2016-09-01 12:44 rcc1
   [root@hdp2 tmp]# hdfs dfs -cat /user/root/a.txt
   [root@hdp2 tmp]# 

• 小结：

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•  本质就是linux文件操作命令