To perform filesystem related tasks, the commands begin with hdfs dfs. The filesystem commands have been designed to behave similarly to the corresponding Unix/Linux filesystem commands.
What is a URI? URI stands for Uniform Resource Identifier. In the commands that are listed as follows, you will observe the use of URI for file locations. The URI syntax to access a file in HDFS is hdfs://namenodehost/parent/child/<file>.
The following are some of the most commonly used HDFS commands:
ls: This command lists files in HDFS.The syntax of the
lscommand ishdfs dfs -ls <args>. The following is the screenshot showing an example of thelscommand:
cat: This command displays the contents of file/files in the terminal.The syntax of the
catcommand ishdfs dfs -cat URI [URI …]. The following is a sample output of thecatcommand:
copyFromLocal: This command copies a file/files from the local filesystem to HDFS.