Hadoop Commands

Hadoop Commands

1.	lsr <path> Behaves like -ls, but recursively displays entries in all subdirectories of path.
2.	du <path> Shows disk usage, in bytes, for all the files which match path; filenames are reported with the full HDFS protocol prefix.
3.	dus <path> Like -du, but prints a summary of disk usage of all files/directories in the path.
4.	mv <src><dest> Moves the file or directory indicated by src to dest, within HDFS.
5.	cp <src> <dest> Copies the file or directory identified by src to dest, within HDFS.
6.	rm <path> Removes the file or empty directory identified by path.
7.	rmr <path> Removes the file or directory identified by path. Recursively deletes any child entries (i.e., files or subdirectories of path).
8.	put <localSrc> <dest> Copies the file or directory from the local file system identified by localSrc to dest within the DFS.
9.	copyFromLocal <localSrc> <dest> Identical to -put
10.	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.
11.	get [-crc] <src> <localDest> Copies the file or directory in HDFS identified by src to the local file system path identified by localDest.
12.	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.
13.	cat <filen-ame> Displays the contents of filename on stdout.
14.	copyToLocal <src> <localDest> Identical to -get
15.	moveToLocal <src> <localDest> Works like -get, but deletes the HDFS copy on success.
16.	mkdir <path> Creates a directory named path in HDFS. Creates any parent directories in path that are missing (e.g., mkdir -p in Linux).
17.	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)
18.	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.
19.	test -[ezd] <path> Returns 1 if path exists; has zero length; or is a directory or 0 otherwise.
20.	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).
21.	tail [-f] <file2name> Shows the last 1KB of file on stdout.
22.	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.
23.	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.
24.	chgrp [-R] group <path>... Sets the owning group for files or directories identified by path.... Sets group recursively if -R is specified.
25.	help <cmd-name> Returns usage information for one of the commands listed above. You must omit the leading '-' character in cmd.