大数据HDFS用户客户端命令行(User Client Commands)详细使用说明

Posted 2023-03-09 笑起来贼好看

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User Commands

概览
命令详解

概览

所有的HDFS命令都是执行bin/hdfs脚本，当执行此脚本时，如果不带任何参数，就会打印使用说明usage。

Usage: hdfs [OPTIONS] SUBCOMMAND [SUBCOMMAND OPTIONS]

  OPTIONS is none or any of:

--buildpaths                       attempt to add class files from build tree
--config dir                       Hadoop config directory
--daemon (start|status|stop)       operate on a daemon
--debug                            turn on shell script debug mode
--help                             usage information
--hostnames list[,of,host,names]   hosts to use in worker mode
--hosts filename                   list of hosts to use in worker mode
--loglevel level                   set the log4j level for this command
--workers                          turn on worker mode

  SUBCOMMAND is one of:


    Admin Commands:

cacheadmin           configure the HDFS cache
crypto               configure HDFS encryption zones
debug                run a Debug Admin to execute HDFS debug commands
dfsadmin             run a DFS admin client
dfsrouteradmin       manage Router-based federation
ec                   run a HDFS ErasureCoding CLI
fsck                 run a DFS filesystem checking utility
haadmin              run a DFS HA admin client
jmxget               get JMX exported values from NameNode or DataNode.
oev                  apply the offline edits viewer to an edits file
oiv                  apply the offline fsimage viewer to an fsimage
oiv_legacy           apply the offline fsimage viewer to a legacy fsimage
storagepolicies      list/get/set/satisfyStoragePolicy block storage policies

    Client Commands:

classpath            prints the class path needed to get the hadoop jar and the required libraries
dfs                  run a filesystem command on the file system
envvars              display computed Hadoop environment variables
fetchdt              fetch a delegation token from the NameNode
getconf              get config values from configuration
groups               get the groups which users belong to
lsSnapshottableDir   list all snapshottable dirs owned by the current user
snapshotDiff         diff two snapshots of a directory or diff the current directory contents with a snapshot
version              print the version

    Daemon Commands:

balancer             run a cluster balancing utility
datanode             run a DFS datanode
dfsrouter            run the DFS router
diskbalancer         Distributes data evenly among disks on a given node
httpfs               run HttpFS server, the HDFS HTTP Gateway
journalnode          run the DFS journalnode
mover                run a utility to move block replicas across storage types
namenode             run the DFS namenode
nfs3                 run an NFS version 3 gateway
portmap              run a portmap service
secondarynamenode    run the DFS secondary namenode
sps                  run external storagepolicysatisfier
zkfc                 run the ZK Failover Controller daemon

SUBCOMMAND may print help when invoked w/o parameters or with -h.

命令详解

classpath

该命令展示hadoop的classpath路径

usage

classpath [--glob|--jar <path>|-h|--help] :
  Prints the classpath needed to get the Hadoop jar and the required
  libraries.
  Options:

  --glob       expand wildcards
  --jar <path> write classpath as manifest in jar named <path>
  -h, --help   print help

此命令调用的是 org.apache.hadoop.util.Classpath 类

[root@spark-31 hadoop-3.3.1]# bin/hdfs classpath
/data/apps/hadoop-3.3.1/etc/hadoop:/data/apps/hadoop-3.3.1/share/hadoop/common/lib/*:/data/apps/hadoop-3.3.1/share/hadoop/common/*:/data/apps/hadoop-3.3.1/share/hadoop/hdfs:/data/apps/hadoop-3.3.1/share/hadoop/hdfs/lib/*:/data/apps/hadoop-3.3.1/share/hadoop/hdfs/*:/data/apps/hadoop-3.3.1/share/hadoop/mapreduce/*:/data/apps/hadoop-3.3.1/share/hadoop/yarn:/data/apps/hadoop-3.3.1/share/hadoop/yarn/lib/*:/data/apps/hadoop-3.3.1/share/hadoop/yarn/*