Basic command of hadoop
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This document provides an overview of basic commands for interacting with Hadoop Distributed File System (HDFS) including: 1) ls to list files, mkdir to create directories, touchz to create empty files, copyFromLocal/put to copy from local to HDFS, cat to view file contents 2) copyToLocal/get to copy from HDFS to local, moveFromLocal to move from local to HDFS, cp to copy within HDFS, mv to move within HDFS 3) rmr to recursively delete directories, du to get file sizes, dus to get total directory size, stat to get file status, and setrep to change replication factor.
Basic command of hadoop
- 1. BASIC COMMAND OF HADOOP ~presented by ahmad
- 2. AGENDA • LS • MKDIR • TOUCHZ • COPYFROMLOCAL (OR) PUT • CAT • COPYTOLOCAL (OR) GET • MOVEFROMLOCAL • CP • MV • RMR • DU • DUS • STAT • SETREP
- 3. ls :This command is used to list all the files. Use lsr for recursive approach. It is useful when we want a hierarchy of a folder. Syntax : bin/hdfs dfs -ls <path> Example: bin/hdfs dfs -ls / mkdir: To create a directory. In Hadoop dfs there is no home directory by default. So let’s first create it. Syntax: bin/hdfs dfs -mkdir <folder name> creating home directory: hdfs/bin -mkdir /user hdfs/bin -mkdir /user/username -> write the username of your computer Example : bin/hdfs dfs -mkdir /ahmad => '/' means absolute path
- 4. Touchz : It creates an empty file. Syntax: bin/hdfs dfs -touchz <file_path> Example: bin/hdfs dfs -touchz /geeks/myfile.txt copyFromLocal (or) put: To copy files/folders from local file system to hdfs store. This is the most important command. Local filesystem means the files present on the OS. Syntax: bin/hdfs dfs -copyFromLocal <local file path> <dest(present on hdfs)> Example: bin/hdfs dfs -put ../Desktop/AI.txt /ahmad cat: To print file contents. Syntax: bin/hdfs dfs -cat <path> Example: bin/hdfs dfs -cat /geeks/AI.txt ->
- 5. copyToLocal (or) get: To copy files/folders from hdfs store to local file system. Syntax: bin/hdfs dfs -copyToLocal <<srcfile(on hdfs)> <local file dest> Example: bin/hdfs dfs -get /geeks/myfile.txt ../Desktop/hero moveFromLocal: This command will move file from local to hdfs. Syntax: bin/hdfs dfs -moveFromLocal <local src> <dest(on hdfs)> Example: bin/hdfs dfs -moveFromLocal ../Desktop/cutAndPaste.txt /geeks cp: This command is used to copy files within hdfs. Lets copy folder geeks to geeks_copied. Syntax: bin/hdfs dfs -cp <src(on hdfs)> <dest(on hdfs)> Example: bin/hdfs -cp /geeks /geeks_copied
- 6. mv: This command is used to move files within hdfs. Lets cut-paste a file myfile.txt from geeks folder to geeks_copied. Syntax : bin/hdfs dfs -mv <src(on hdfs)> <src(on hdfs)> Example: bin/hdfs -mv /geeks/myfile.txt /geeks_copied rmr: This command deletes a file from HDFS recursively. It is very useful command when you want to delete a non-empty directory. Syntax : bin/hdfs dfs -rmr <filename/directoryName> Example: bin/hdfs dfs -rmr /geeks_copied du: It will give the size of each file in directory. Syntax : bin/hdfs dfs -du <dirName> Example: bin/hdfs dfs -du /geeks
- 7. dus: This command will give the total size of directory/file. Syntax: bin/hdfs dfs -dus <dirName> Example: bin/hdfs dfs -dus /geeks stat: It will give the last modified time of directory or path. In short it will give stats of the directory or file. Syntax: bin/hdfs dfs -stat <hdfs file> Example: bin/hdfs dfs -stat /geeks setrep: This command is used to change the replication factor of a file/directory in HDFS. By default it is 3 for anything which is stored in HDFS (as set in hdfs core-site.xml). Syntax: bin/hdfs dfs -setrep -R -w 6 geeks.txt Example: bin/hdfs dfs -setrep -R 4 /geeks