命令格式:
hadoop fs -command -option args
appendToFile
Usage: hadoop fs -appendToFile <localsrc> ... <dst>
退出状态：
0-成功
1-失败
$ hadoop fs -appendToFile 1130.txt hadoopfile
$ hadoop fs -appendToFile - hadoopfile #从标准输入中读取数据，然后追加到hadoopfile文件末尾
$ hadoop fs -appendToFile test.c file.txt hadoopfile #将test.c和file.txt文件内容追加到hadoopfile文件末尾
cat
Usage: hadoop fs -cat URI [URI ...]
退出状态：
0-成功
1-失败
$ hadoop fs -cat file:///home/hadoop/file.txt hadoopfile #file:///就表示本地文件系统的/目录
checksum
Usage: hadoop fs -checksum URI
Returns the checksum information of a file.
Example:
hadoop fs -checksum hdfs://nn1.example.com/file1
hadoop fs -checksum file:///etc/hosts
ls
Usage: hadoop fs -ls [-d] [-h] [-R] <args>
Options:
-d: Directories are listed as plain files.
-h: Format file sizes in a human-readable fashion (eg 64.0m instead of 67108864).
-R: Recursively list subdirectories encountered.
For a file ls returns stat on the file with the following format:
permissions number_of_replicas userid groupid filesize modification_date modification_time filename
For a directory it returns list of its direct children as in Unix. A directory is listed as:
permissions userid groupid modification_date modification_time dirname
Files within a directory are order by filename by default.
Example:
hadoop fs -ls /user/hadoop/file1
Exit Code:
Returns 0 on success and -1 on error.
mkdir
Usage: hadoop fs -mkdir [-p] <paths>
Takes path uri’s as argument and creates directories.
Options:
The -p option behavior is much like Unix mkdir -p, creating parent directories along the path.
Example:
hadoop fs -mkdir /user/hadoop/dir1 /user/hadoop/dir2
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.
usage
Usage: hadoop fs -usage command
Return the help for an individual command.