Hadoop HDFS 的shell命令

谁践踏了优雅 2023-10-04 19:04 49阅读 0赞

### Hadoop HDFS 的shell命令 ###

#### 文章目录 ####

*   *  Hadoop HDFS 的shell命令
     *   *  一、命令说明
         *  二、上传文件
         *  三、下载文件
         *  四、新建、删除、查看等

通过shell操作HDFS的语法可以有两种  
1.hadoop fs \[…\]  
2.hdfs dfs \[…\]  
输入hadoop fs或者hdfs fs之后可以返回命令大全

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] [-t <thread count>] <localsrc> ... <dst>]
            [-copyToLocal [-f] [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
            [-count [-q] [-h] [-v] [-t [<storage type>]] [-u] [-x] [-e] <path> ...]
            [-cp [-f] [-p | -p[topax]] [-d] <src> ... <dst>]
            [-createSnapshot <snapshotDir> [<snapshotName>]]
            [-deleteSnapshot <snapshotDir> <snapshotName>]
            [-df [-h] [<path> ...]]
            [-du [-s] [-h] [-v] [-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>]
            [-head <file>]
            [-help [cmd ...]]
            [-ls [-C] [-d] [-h] [-q] [-R] [-t] [-S] [-r] [-u] [-e] [<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] [-s <sleep interval>] <file>]
            [-test -[defsz] <path>]
            [-text [-ignoreCrc] <src> ...]
            [-touch [-a] [-m] [-t TIMESTAMP ] [-c] <path> ...]
            [-touchz <path> ...]
            [-truncate [-w] <length> <path> ...]
            [-usage [cmd ...]]

下面介绍几个常用的命令

#### 一、命令说明 ####

\-help

hadoop fs -help [command]

如果对于某个命令不熟悉，想要知道具体的用法，可以使用 --help命令查看  
比如：查看ls的命令使用说明

hadoop fs -help ls

-ls [-C] [-d] [-h] [-q] [-R] [-t] [-S] [-r] [-u] [-e] [<path> ...] :
      List the contents that match the specified file pattern. If path is not
      specified, the contents of /user/<currentUser> will be listed. For a directory a
      list of its direct children is returned (unless -d option is specified).
    
      Directory entries are of the form:
            permissions - userId groupId sizeOfDirectory(in bytes)
      modificationDate(yyyy-MM-dd HH:mm) directoryName
    
      and file entries are of the form:
            permissions numberOfReplicas userId groupId sizeOfFile(in bytes)
      modificationDate(yyyy-MM-dd HH:mm) fileName
    
        -C  Display the paths of files and directories only.
        -d  Directories are listed as plain files.
        -h  Formats the sizes of files in a human-readable fashion
            rather than a number of bytes.
        -q  Print ? instead of non-printable characters.
        -R  Recursively list the contents of directories.
        -t  Sort files by modification time (most recent first).
        -S  Sort files by size.
        -r  Reverse the order of the sort.
        -u  Use time of last access instead of modification for
            display and sorting.
        -e  Display the erasure coding policy of files and directories.

#### 二、上传文件 ####

1.  \-moveFromLocal：从本地剪切粘贴到 HDFS
2.  \-copyFromLocal：从本地文件系统中拷贝文件到 HDFS 路径去
3.  \-put：等同于 copyFromLocal，生产环境更习惯用 put
4.  \-appendToFile：追加一个文件到已经存在的文件末尾

#### 三、下载文件 ####

1.  \-copyToLocal：从 HDFS 拷贝到本地
2.  \-get：等同于 copyToLocal，生产环境更习惯用 get

#### 四、新建、删除、查看等 ####

基本和linux的shell命令一样了  
比如：  
ls：查看目录信息  
cat：输出文件内容  
mkdir：创建文件夹  
touch：创建文件  
rm：删除文件  
mv：移动文件  
cp：复制文件  
chomd：修改文件权限  
chown：修改用户权限  
tail：显示文件末尾1kb  
du：显示文件大小  
关于du命令有文件和文件夹区分  
看一下du的使用：

hadoop fs -help du

-du [-s] [-h] [-v] [-x] <path> ... :
      Show the amount of space, in bytes, used by the files that match the specified
      file pattern. The following flags are optional:
    
      -s  Rather than showing the size of each individual file that matches the
          pattern, shows the total (summary) size.
      -h  Formats the sizes of files in a human-readable fashion rather than a number
          of bytes.
      -v  option displays a header line.
      -x  Excludes snapshots from being counted.
    
      Note that, even without the -s option, this only shows size summaries one level
      deep into a directory.
    
      The output is in the form
            size    disk space consumed     name(full path)

首先可以看命令返回的结果格式是：

The output is in the form
            size    disk space consumed     name(full path)

就是单副本大小、多副本大小、文件路径  
可以看到这个命令的参数  
**-s：如果是一个文件夹，会显示文件夹的总大小**

hadoop fs -du -s /

结果：

658519139  1975557417  /

**-h：会格式化结果**

hadoop fs -du -s -h /

结果：

628.0 M  1.8 G  /

**-v：显示出表头**

hadoop fs -du -s -h -v /