Hadoop – Command Reference

There are many more commands in “$HADOOP_HOME/bin/hadoop fs” than are demonstrated here, although these basic operations will get you started. Running ./bin/hadoop dfs with no additional arguments will list all the commands that can be run with the FsShell system. Furthermore, $HADOOP_HOME/bin/hadoop fs -help commandName will display a short usage summary for the operation in question, if you are stuck.

A table of all the operations is shown below. The following conventions are used for parameters −

"<path>" means any file or directory name. 
"<path>..." means one or more file or directory names. 
"<file>" means any filename. 
"<src>" and "<dest>" are path names in a directed operation. 
"<localSrc>" and "<localDest>" are paths as above, but on the local file system. 

All other files and path names refer to the objects inside HDFS.

Sr.NoCommand & Description
1-ls <path>Lists the contents of the directory specified by path, showing the names, permissions, owner, size and modification date for each entry.
2-lsr <path>Behaves like -ls, but recursively displays entries in all subdirectories of path.
3-du <path>Shows disk usage, in bytes, for all the files which match path; filenames are reported with the full HDFS protocol prefix.
4-dus <path>Like -du, but prints a summary of disk usage of all files/directories in the path.
5-mv <src><dest>Moves the file or directory indicated by src to dest, within HDFS.
6-cp <src> <dest>Copies the file or directory identified by src to dest, within HDFS.
7-rm <path>Removes the file or empty directory identified by path.
8-rmr <path>Removes the file or directory identified by path. Recursively deletes any child entries (i.e., files or subdirectories of path).
9-put <localSrc> <dest>Copies the file or directory from the local file system identified by localSrc to dest within the DFS.
10-copyFromLocal <localSrc> <dest>Identical to -put
11-moveFromLocal <localSrc> <dest>Copies the file or directory from the local file system identified by localSrc to dest within HDFS, and then deletes the local copy on success.
12-get [-crc] <src> <localDest>Copies the file or directory in HDFS identified by src to the local file system path identified by localDest.
13-getmerge <src> <localDest>Retrieves all files that match the path src in HDFS, and copies them to a single, merged file in the local file system identified by localDest.
14-cat <filen-ame>Displays the contents of filename on stdout.
15-copyToLocal <src> <localDest>Identical to -get
16-moveToLocal <src> <localDest>Works like -get, but deletes the HDFS copy on success.
17-mkdir <path>Creates a directory named path in HDFS.Creates any parent directories in path that are missing (e.g., mkdir -p in Linux).
18-setrep [-R] [-w] rep <path>Sets the target replication factor for files identified by path to rep. (The actual replication factor will move toward the target over time)
19-touchz <path>Creates a file at path containing the current time as a timestamp. Fails if a file already exists at path, unless the file is already size 0.
20-test -[ezd] <path>Returns 1 if path exists; has zero length; or is a directory or 0 otherwise.
21-stat [format] <path>Prints information about path. Format is a string which accepts file size in blocks (%b), filename (%n), block size (%o), replication (%r), and modification date (%y, %Y).
22-tail [-f] <file2name>Shows the last 1KB of file on stdout.
23-chmod [-R] mode,mode,… <path>…Changes the file permissions associated with one or more objects identified by path…. Performs changes recursively with R. mode is a 3-digit octal mode, or {augo}+/-{rwxX}. Assumes if no scope is specified and does not apply an umask.
24-chown [-R] [owner][:[group]] <path>…Sets the owning user and/or group for files or directories identified by path…. Sets owner recursively if -R is specified.
25-chgrp [-R] group <path>…Sets the owning group for files or directories identified by path…. Sets group recursively if -R is specified.
26-help <cmd-name>Returns usage information for one of the commands listed above. You must omit the leading ‘-‘ character in cmd.

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