大数据笔记：HDFS shelll常用命令的使用
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HDFS shelll常用命令的使用
如何使用hdfs
dfs
不会用，按回车
[japson@localhost sbin]$ hdfs
Usage: hdfs [--config confdir] COMMAND
where COMMAND is one of:
dfs run a filesystem command on the file systems supported in Hadoop.
namenode -format format the DFS filesystem
secondarynamenode run the DFS secondary namenode
namenode run the DFS namenode
journalnode run the DFS journalnode
zkfc run the ZK Failover Controller daemon
datanode run a DFS datanode
dfsadmin run a DFS admin client
haadmin run a DFS HA admin client
fsck run a DFS filesystem checking utility
balancer run a cluster balancing utility
jmxget get JMX exported values from NameNode or DataNode.
mover run a utility to move block replicas across
storage types
oiv apply the offline fsimage viewer to an fsimage
oiv_legacy apply the offline fsimage viewer to an legacy fsimage
oev apply the offline edits viewer to an edits file
fetchdt fetch a delegation token from the NameNode
getconf get config values from configuration
groups get the groups which users belong to
snapshotDiff diff two snapshots of a directory or diff the
current directory contents with a snapshot
lsSnapshottableDir list all snapshottable dirs owned by the current user
Use -help to see options
portmap run a portmap service
nfs3 run an NFS version 3 gateway
cacheadmin configure the HDFS cache
crypto configure HDFS encryption zones
storagepolicies list/get/set block storage policies
version print the version
Most commands print help when invoked w/o parameters.选择dfs命令
hdfs dfs
[japson@localhost sbin]$ hdfs dfs
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] <localsrc> ... <dst>]
[-copyToLocal [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
[-count [-q] [-h] [-v] <path> ...]
[-cp [-f] [-p | -p[topax]] <src> ... <dst>]
[-createSnapshot <snapshotDir> [<snapshotName>]]
[-deleteSnapshot <snapshotDir> <snapshotName>]
[-df [-h] [<path> ...]]
[-du [-s] [-h] <path> ...]
[-expunge]
[-find <path> ... <expression> ...]
[-get [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]
[-getfacl [-R] <path>]
[-getfattr [-R] {-n name | -d} [-e en] <path>]
[-getmerge [-nl] <src> <localdst>]
[-help [cmd ...]]
[-ls [-d] [-h] [-R] [<path> ...]]
[-mkdir [-p] <path> ...]
[-moveFromLocal <localsrc> ... <dst>]
[-moveToLocal <src> <localdst>]
[-mv <src> ... <dst>]
[-put [-f] [-p] [-l] <localsrc> ... <dst>]
[-renameSnapshot <snapshotDir> <oldName> <newName>]
[-rm [-f] [-r|-R] [-skipTrash] <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> ...]
[-usage [cmd ...]]
Generic options supported are
-conf <configuration file> specify an application configuration file
-D <property=value> use value for given property
-fs <local|namenode:port> specify a namenode
-jt <local|resourcemanager:port> specify a ResourceManager
-files <comma separated list of files> specify comma separated files to be copied to the map reduce cluster
-libjars <comma separated list of jars> specify comma separated jar files to include in the classpath.
-archives <comma separated list of archives> specify comma separated archives to be unarchived on the compute machines.
The general command line syntax is
bin/hadoop command [genericOptions] [commandOptions]
下面演示一些常用命令
在data目录下创建一个hello.txt：
hadoop welcome
hadop hdfs mapreduce
hadoop hdfs查看文件系统上面现在有的东西，使用命令hdfs dfs -ls /：
[japson@localhost data]$ hdfs dfs -ls /
18/05/24 02:50:08 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable但是什么都没有。然后我们将hello.txt传入到文件系统的根目录上
[japson@localhost data]$ hdfs dfs -put hello.txt /我们再次查看，发现hello.txt已经被上传上去了：
[japson@localhost data]$ hdfs dfs -ls /
18/05/24 02:54:31 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Found 1 items
-rw-r--r-- 1 japson supergroup 48 2018-05-24 02:52 /hello.txt我们也可以查看这个文件内容hdfs dfs -cat /hello.txt：
[japson@localhost data]$ hdfs dfs -cat /hello.txt
18/05/24 03:00:00 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
hadoop welcome
hadop hdfs mapreduce
hadoop hdfs也可以创建一个目录
[japson@localhost data]$ hdfs dfs -mkdir /test递归地创建目录：
[japson@localhost data]$ hdfs dfs -ls /test/a/b当然也可以递归地查看
[japson@localhost data]$ hdfs dfs -ls -R /也可以使用copyFromLocal命令将文件进行复制
[japson@localhost data]$ hdfs dfs -copyFromLoacl hello.txt /test/a/b/h.txt从文件系统中将内容复制到本地，使用get命令，然后就可以在本地看到了下载来的文件：
[japson@localhost data]$ hdfs dfs -get /test/a/b/h.txt