Shulou(Shulou.com)06/03 Report--

Brief introduction:

The HDFS file system provides quite a number of shell operation commands, which greatly facilitates programmers and system managers to view and modify files on HDFS. Further, the name and format of HDFS's operation commands are quite consistent with those of Unix/Linux 's commands, so the cost of learning HDFS commands is greatly reduced. 1. Command help [hadoop@hadoop000 ~] $hdfs dfsUsage: hadoop fs [generic options] [- appendToFile...] [- cat [- ignoreCrc]...] [- checksum...] [- chgrp [- R] GROUP PATH...] [- chmod [- R] PATH...] [- chown [- R] [OWNER] [: [GROUP]] PATH... ] [- copyFromLocal [- f] [- p] [- l] [- d]...] [- copyToLocal [- f] [- p] [- ignoreCrc] [- crc]...] [- count [- Q] [- h] [- v] [- t []] [- u] [- x]...] [- cp [- f] [- p |-p [topax] [- d]...] [- createSnapshot []] [- deleteSnapshot] [- df [- h] [...]] [- du [- s] [- h] [- x]...] [- expunge] [- find...] [- get [- f] ] [- p] [- ignoreCrc] [- crc]...] [- getfacl [- R]] [- getfattr [- R] {- n name |-d} [- e en]] [- getmerge [- nl] [- skip-empty-file]] [- help [cmd...]] [- ls [- C] [- d] [- h] [- Q] [- R] [- t] [- S] [- r] [- u] [..] [- mkdir [- p].] [- moveFromLocal...] [- moveToLocal] [- mv.] [- put [- f] [- p] [- l] [- d]. ] [- renameSnapshot] [- rm [- f] [- r |-R] [- skipTrash] [- safely]...] [- rmdir [--ignore-fail-on-non-empty]...] [- setfacl [- R] [{- b |-k} {- m |-x}] | [--set]] [- setfattr {- n name [- v value] | |-x name}] [- setrep [- R] [- w].] [- stat [format].] [- tail [- f]] [- test-[defsz]] [- text [- ignoreCrc].] [- touchz.] [- truncate [- w].] [ -usage [cmd...] # Note: hdfs dfs is equivalent to hadoop fs2. File manipulation command case

Hdfs dfs-copyFromLocal / local/data / hdfs/data: upload local files to hdfs (the original path can only be one file)

Hdfs dfs-put / tmp/ / hdfs/: different from copyFromLocal, the original path of put can be a folder, etc.

Hadoop fs-ls /: view the root directory file

Hadoop fs-ls / tmp/data: view the / tmp/data directory

Hadoop fs-cat / tmp/a.txt: view a.txt, same as-text

Hadoop fs-mkdir dir: create directory dir

Hadoop fs-get / aaa/jdk.tar.gz: equivalent to copyToLocal, which downloads files from hdfs to local

Hadoop fs-df-h /: statistics on the free space of the file system

Hadoop fs-cp / aaa/jdk.tar.gz / bbb/jdk.tar.gz.2: copy hdfs from one path of hdfs to another path

Hadoop fs-mv / aaa/jdk.tar.gz /: move files in the hdfs directory

Hadoop fs-du-s-h / aaa/*: size information of statistical folders

Hadoop fs-rm-r / aaa/bbb/: delete files or folders

Hadoop fs-rmdir / aaa/bbb/ccc: delete a directory

Hadoop fs-tail / weblog/access_log.1: displays the end of a file

3. Administrative command # command helps [hadoop@hadoop000 ~] $hdfs dfsadminUsage: hdfs dfsadminNote: Administrative commands can only be run as the HDFS superuser. [- report [- live] [- dead] [- decommissioning]] [- safemode] [- saveNamespace] [- rollEdits] [- restoreFailedStorage true | false | check] [- refreshNodes] [- setQuota.] [- clrQuota.] [- setSpaceQuota [- storageType].] [- clrSpaceQuota [- storageType].] [ -finalizeUpgrade] [- rollingUpgrade []] [- refreshServiceAcl] [- refreshUserToGroupsMappings] [- refreshSuperUserGroupsConfiguration] [- refreshCallQueue] [- refresh [arg1..argn] [- reconfig] [- printTopology] [- refreshNamenodes datanode_host:ipc_port] [- deleteBlockPool datanode_host:ipc_port blockpoolId [force]] [- setBalancerBandwidth] [- getBalancerBandwidth] [- fetchImage] [- allowSnapshot] [- disallowSnapshot] [- shutdownDatanode [upgrade]] [- evictWriters] [- getDatanodeInfo] [- metasave filename] [- triggerBlockReport [- incremental]] [- help [cmd]]

Hdfs dfsadmin-report: show all dataNode

Hdfs dfsadmin-safemode leave: leave safe mode

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