hadoop命令帮助

安装完hadoop后，在hadoop的bin目录下有一系列命令：

container-executor  hadoop  hadoop.cmd  hdfs  hdfs.cmd  mapred  mapred.cmd  rcc  test-container-executor  yarn  yarn.cmd

知道这些命令有助于理解hadoop的概念，命令如下：

1. hadoop 命令帮助

 bin/hadoop -help
Usage: hadoop [--config confdir] COMMAND
       where COMMAND is one of:
  fs                   run a generic filesystem user client
  version              print the version
  jar <jar>            run a jar file
  checknative [-a|-h]  check native hadoop and compression libraries availability
  distcp <srcurl> <desturl> copy file or directories recursively
  archive -archiveName NAME -p <parent path> <src>* <dest> create a hadoop archive
  classpath            prints the class path needed to get the
  credential           interact with credential providers
                       Hadoop jar and the required libraries
  daemonlog            get/set the log level for each daemon
  trace                view and modify Hadoop tracing settings
 or
  CLASSNAME            run the class named CLASSNAME

Most commands print help when invoked w/o parameters.

1.1 hadoop fs命令帮助

 bin/hadoop fs -help
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] <path> ...]
        [-cp [-f] [-p | -p[topax]] <src> ... <dst>]
        [-createSnapshot <snapshotDir> [<snapshotName>]]
        [-deleteSnapshot <snapshotDir> <snapshotName>]
        [-df [-h] [<path> ...]]
        [-du [-s] [-h] <path> ...]
        [-expunge]
        [-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 ...]]

-appendToFile <localsrc> ... <dst> :
  Appends the contents of all the given local files to the given dst file. The dst
  file will be created if it does not exist. If <localSrc> is -, then the input is
  read from stdin.

-cat [-ignoreCrc] <src> ... :
  Fetch all files that match the file pattern <src> and display their content on
  stdout.

-checksum <src> ... :
  Dump checksum information for files that match the file pattern <src> to stdout.
  Note that this requires a round-trip to a datanode storing each block of the
  file, and thus is not efficient to run on a large number of files. The checksum
  of a file depends on its content, block size and the checksum algorithm and
  parameters used for creating the file.

-chgrp [-R] GROUP PATH... :
  This is equivalent to -chown ... :GROUP ...

-chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH... :
  Changes permissions of a file. This works similar to the shell's chmod command
  with a few exceptions.

  -R           modifies the files recursively. This is the only option currently
               supported.
  <MODE>       Mode is the same as mode used for the shell's command. The only
               letters recognized are 'rwxXt', e.g. +t,a+r,g-w,+rwx,o=r.
  <OCTALMODE>  Mode specifed in  or  digits. If  digits, the first may be  or
                to turn the sticky bit on or off, respectively.  Unlike the
               shell command, it is not possible to specify only part of the
               mode, e.g.  is same as u=rwx,g=rx,o=r.                         

  If none of 'augo' is specified, 'a' is assumed and unlike the shell command, no
  umask is applied.

-chown [-R] [OWNER][:[GROUP]] PATH... :
  Changes owner and group of a file. This is similar to the shell's chown command
  with a few exceptions.

  -R  modifies the files recursively. This is the only option currently
      supported.                                                                 

  If only the owner or group is specified, then only the owner or group is
  modified. The owner and group names may only consist of digits, alphabet, and
  any of [-_./@a-zA-Z0-]. The names are case sensitive.

  WARNING: Avoid using '.' to separate user name and group though Linux allows it.
  If user names have dots in them and you are using local file system, you might
  see surprising results since the shell command 'chown' is used for local files.

-copyFromLocal [-f] [-p] [-l] <localsrc> ... <dst> :
  Identical to the -put command.

-copyToLocal [-p] [-ignoreCrc] [-crc] <src> ... <localdst> :
  Identical to the -get command.

-count [-q] [-h] <path> ... :
  Count the number of directories, files and bytes under the paths
  that match the specified file pattern.  The output columns are:
  DIR_COUNT FILE_COUNT CONTENT_SIZE FILE_NAME or
  QUOTA REMAINING_QUOTA SPACE_QUOTA REMAINING_SPACE_QUOTA
        DIR_COUNT FILE_COUNT CONTENT_SIZE FILE_NAME
  The -h option shows file sizes in human readable format.

-cp [-f] [-p | -p[topax]] <src> ... <dst> :
  Copy files that match the file pattern <src> to a destination.  When copying
  multiple files, the destination must be a directory. Passing -p preserves status
  [topax] (timestamps, ownership, permission, ACLs, XAttr). If -p is specified
  with no <arg>, then preserves timestamps, ownership, permission. If -pa is
  specified, then preserves permission also because ACL is a super-set of
  permission. Passing -f overwrites the destination if it already exists. raw
  namespace extended attributes are preserved if () they are supported (HDFS
  only) and, () all of the source and target pathnames are in the /.reserved/raw
  hierarchy. raw namespace xattr preservation is determined solely by the presence
  (or absence) of the /.reserved/raw prefix and not by the -p option.

-createSnapshot <snapshotDir> [<snapshotName>] :
  Create a snapshot on a directory

-deleteSnapshot <snapshotDir> <snapshotName> :
  Delete a snapshot from a directory

-df [-h] [<path> ...] :
  Shows the capacity, free and used space of the filesystem. If the filesystem has
  multiple partitions, and no path to a particular partition is specified, then
  the status of the root partitions will be shown.

  -h  Formats the sizes of files in a human-readable fashion rather than a number
      of bytes.                                                                  

-du [-s] [-h] <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.                                                                  

  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    name(full path)

-expunge :
  Empty the Trash

-get [-p] [-ignoreCrc] [-crc] <src> ... <localdst> :
  Copy files that match the file pattern <src> to the local name.  <src> is kept.
  When copying multiple files, the destination must be a directory. Passing -p
  preserves access and modification times, ownership and the mode.

-getfacl [-R] <path> :
  Displays the Access Control Lists (ACLs) of files and directories. If a
  directory has a default ACL, then getfacl also displays the default ACL.

  -R      List the ACLs of all files and directories recursively.
  <path>  File or directory to list.                              

-getfattr [-R] {-n name | -d} [-e en] <path> :
  Displays the extended attribute names and values (if any) for a file or
  directory.

  -R             Recursively list the attributes for all files and directories.
  -n name        Dump the named extended attribute value.
  -d             Dump all extended attribute values associated with pathname.
  -e <encoding>  Encode values after retrieving them.Valid encodings are "text",
                 "hex", and "base64". Values encoded as text strings are enclosed
                 in double quotes ("), and values encoded as hexadecimal and
                 base64 are prefixed with 0x and 0s, respectively.
  <path>         The file or directory.                                          

-getmerge [-nl] <src> <localdst> :
  Get all the files in the directories that match the source file pattern and
  merge and sort them to only one file on local fs. <src> is kept.

  -nl  Add a newline character at the end of each file. 

-help [cmd ...] :
  Displays help for given command or all commands if none is specified.

-ls [-d] [-h] [-R] [<path> ...] :
  List the contents that match the specified file pattern. If path is not
  specified, the contents of /user/<currentUser> will be listed. 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

  -d  Directories are listed as plain files.
  -h  Formats the sizes of files in a human-readable fashion rather than a number
      of bytes.
  -R  Recursively list the contents of directories.                              

-mkdir [-p] <path> ... :
  Create a directory in specified location.

  -p  Do not fail if the directory already exists 

-moveFromLocal <localsrc> ... <dst> :
  Same as -put, except that the source is deleted after it's copied.

-moveToLocal <src> <localdst> :
  Not implemented yet

-mv <src> ... <dst> :
  Move files that match the specified file pattern <src> to a destination <dst>.
  When moving multiple files, the destination must be a directory.

-put [-f] [-p] [-l] <localsrc> ... <dst> :
  Copy files from the local file system into fs. Copying fails if the file already
  exists, unless the -f flag is given.
  Flags:

  -p  Preserves access and modification times, ownership and the mode.
  -f  Overwrites the destination if it already exists.
  -l  Allow DataNode to lazily persist the file to disk. Forces
         replication factor of . This flag will result in reduced
         durability. Use with care.

-renameSnapshot <snapshotDir> <oldName> <newName> :
  Rename a snapshot from oldName to newName

-rm [-f] [-r|-R] [-skipTrash] <src> ... :
  Delete all files that match the specified file pattern. Equivalent to the Unix
  command "rm <src>"

  -skipTrash  option bypasses trash, if enabled, and immediately deletes <src>
  -f          If the file does not exist, do not display a diagnostic message or
              modify the exit status to reflect an error.
  -[rR]       Recursively deletes directories                                    

-rmdir [--ignore-fail-on-non-empty] <dir> ... :
  Removes the directory entry specified by each directory argument, provided it is
  empty.

-setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>] :
  Sets Access Control Lists (ACLs) of files and directories.
  Options:

  -b          Remove all but the base ACL entries. The entries for user, group
              and others are retained for compatibility with permission bits.
  -k          Remove the default ACL.
  -R          Apply operations to all files and directories recursively.
  -m          Modify ACL. New entries are added to the ACL, and existing entries
              are retained.
  -x          Remove specified ACL entries. Other ACL entries are retained.
  --set       Fully replace the ACL, discarding all existing entries. The
              <acl_spec> must include entries for user, group, and others for
              compatibility with permission bits.
  <acl_spec>  Comma separated list of ACL entries.
  <path>      File or directory to modify.                                       

-setfattr {-n name [-v value] | -x name} <path> :
  Sets an extended attribute name and value for a file or directory.

  -n name   The extended attribute name.
  -v value  The extended attribute value. There are three different encoding
            methods for the value. If the argument is enclosed in double quotes,
            then the value is the string inside the quotes. If the argument is
            prefixed with 0x or 0X, then it is taken as a hexadecimal number. If
            the argument begins with 0s or 0S, then it is taken as a base64
            encoding.
  -x name   Remove the extended attribute.
  <path>    The file or directory.                                               

-setrep [-R] [-w] <rep> <path> ... :
  Set the replication level of a file. If <path> is a directory then the command
  recursively changes the replication factor of all files under the directory tree
  rooted at <path>.

  -w  It requests that the command waits for the replication to complete. This
      can potentially take a very long time.
  -R  It is accepted for backwards compatibility. It has no effect.              

-stat [format] <path> ... :
  Print statistics about the file/directory at <path> in the specified format.
  Format accepts filesize in blocks (%b), group name of owner(%g), filename (%n),
  block size (%o), replication (%r), user name of owner(%u), modification date
  (%y, %Y)

-tail [-f] <file> :
  Show the last 1KB of the file.

  -f  Shows appended data as the file grows. 

-test -[defsz] <path> :
  Answer various questions about <path>, with result via exit status.
    -d  return  if <path> is a directory.
    -e  return  if <path> exists.
    -f  return  if <path> is a file.
    -s  return  if file <path> is greater than zero bytes in size.
    -z  return  if file <path> is zero bytes in size, else return .

-text [-ignoreCrc] <src> ... :
  Takes a source file and outputs the file in text format.
  The allowed formats are zip and TextRecordInputStream and Avro.

-touchz <path> ... :
  Creates a file of zero length at <path> with current time as the timestamp of
  that <path>. An error is returned if the file exists with non-zero length

-usage [cmd ...] :
  Displays the usage for given command or all commands if none is specified.

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]

例如：查看dfs文件目录

bin/hadoop fs -ls /

2. hdfs命令帮助

bin/hdfs -help
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  gateway
  cacheadmin           configure the HDFS cache
  crypto               configure HDFS encryption zones
  storagepolicies      get all the existing block storage policies
  version              print the version

Most commands print help when invoked w/o parameters.

3. mapred命令帮助

 bin/mapred -help
Usage: mapred [--config confdir] COMMAND
       where COMMAND is one of:
  pipes                run a Pipes job
  job                  manipulate MapReduce jobs
  queue                get information regarding JobQueues
  classpath            prints the class path needed for running
                       mapreduce subcommands
  historyserver        run job history servers as a standalone daemon
  distcp <srcurl> <desturl> copy file or directories recursively
  archive -archiveName NAME -p <parent path> <src>* <dest> create a hadoop archive
  hsadmin              job history server admin interface

Most commands print help when invoked w/o parameters.

4. yarn命令帮助

bin/yarn -help
Usage: yarn [--config confdir] COMMAND
where COMMAND is one of:
  resourcemanager -format-state-store   deletes the RMStateStore
  resourcemanager                       run the ResourceManager
  nodemanager                           run a nodemanager on each slave
  timelineserver                        run the timeline server
  rmadmin                               admin tools
  version                               print the version
  jar <jar>                             run a jar file
  application                           prints application(s)
                                        report/kill application
  applicationattempt                    prints applicationattempt(s)
                                        report
  container                             prints container(s) report
  node                                  prints node report(s)
  queue                                 prints queue information
  logs                                  dump container logs
  classpath                             prints the class path needed to
                                        get the Hadoop jar and the
                                        required libraries
  daemonlog                             get/set the log level for each
                                        daemon
 or
  CLASSNAME                             run the class named CLASSNAME
Most commands print help when invoked w/o parameters.