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Hadoop different Commands used in HDFS
Question Posted on 02 Oct 2019

Home >> BigData >> Hadoop >> Hadoop different Commands used in HDFS



Hadoop different Commands used in HDFS
Below are the different commands which is used in Hadoop. Before this i have mention the different syntax used in below commands.
"< path>" This mean file or directory name.
"< path>..." This means 1 or more file or directory names.
"< file>" This means any filename.
"< src>" and "< dest>" These are path names in a directed operation.
"< localSrc>" and "< localDest>" These are paths as above placed on the local file system.
Now the list of commands

(1)-ls < path>:-Lists the contents of the directory specified by path and shows the names, permissions, owner, size and modification date for each entry placed in the path.

(2)-lsr < path>:-This is same as -ls but r will helps in recursively displays entries in all subdirectories of path.

(3)-du < path>:-This will shows Shows disk usage, in bytes, for all the files given in the match path. And filenames are reported with the full HDFS protocol prefix.

(4)-dus < path>:-It is same as -du but will prints summary of dis usage of all files directories in the given path.

(5)-mv < src>< dest>:-This command will moves the file or directory from defined src to dest in HDFS.

(6)-cp < src>< dest>:-This will copies the files or directory with given src to dest in HDFS.

(7)-rm < path>:-This command will Removes the file or empty directory at given path.

(8)-rmr < path>:-This will do the same as above command but will delete files rom subdirectory too.

(9)-put < localSrc> < dest>:-This will copies the files or directory from local file system which is define in localSrc to dest in HDFS.

(10)-copyFromLocal < localSrc> < dest>:-This is same as -put

(11)-moveFromLocal < localSrc> < dest>:-This will copies the files or directory from local file system which is define in localSrc to dest in HDFS in addition will deletes the local copy on success.

(12)-get [-crc] < src> < localDest>:-This will copies the file or directory in HDFS identified by src to the local file system path identified by localDest.

(13)-getmerge < src> < localDest>:-This will 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>:-This will display the contents of filename on stdout.

(15)-copyToLocal < src> < localDest>:-This is same as command no 12.

(16)-moveToLocal < src> < localDest>:-This will do the same as -get but will deletes the HDFS copy on success.

(17)-mkdir < path>:-This will creates directory named path in HDFS.

(18)-setrep [-R] [-w] rep < path>:-This will sets the target replication factor for files identified by the path to rep.

(19)-touchz < path>:-This will 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>:-This will used to chec the path exists or not if returns 1 if it is exists. If this have zero length or is a directory. 0 otherwise.

(21)-stat[format]< path>:-This will 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>:-This shows the last 1KB of file on stdout.

(23)-chmod [-R] mode,mode,... < path>...:-This will Change the file permissions associated with one or more objects identified by path.Performs changes recursively with R. mode is a 3-digit octal mode

(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>:-This will returns usage information for one of the commands listed above. we must omit the leading '-' character in cmd.


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