[SOLVED] How To Run Shell Command In Scala From The Code Level – Check Great Code Snippet In 1 Minute?

In this post I will show how to run shell command in Scala".

Introduction

Shell

A shell" is a command-line interface" (CLI) that allows users to interact with an operating system (OS). It is a program that reads and executes commands entered by the user" and provides a way to control and automate various tasks on a computer.

Some popular examples of shells include:

• Bash" (Bourne Again shell"): A Unix shell that is commonly used on Linux and macOS" systems
• PowerShell: A shell developed by Microsoft that is used on Windows" systems
• C shell": A shell that was developed at UC Berkeley and is available on Unix and Linux" systems

Shells provide a number of features that make it easier to work with an OS, including:

• A command-line interface": Users can enter commands using a keyboard rather than using a graphical user" interface (GUI).
• Command history: Shells typically keep a history of the commands that have been entered, allowing users to easily reuse or edit previous commands.
• Command completion: Shells often provide a way to auto-complete commands and file names, making it easier to enter long or complex commands.
• Scripting support: Shells provide a way to automate tasks by writing scripts that can be executed from the command line".

What Is Scala?

Scala is a high-level programming language that mixes object-oriented and functional programming". Scala’s static types help complicated applications avoid problems, and its JVM and JavaScript runtimes allow you to construct high-performance systems with simple access to a vast library ecosystem.

Scala is a multi-paradigm programming language that was created to describe common programming" patterns in a short, expressive, and type-safe manner. It combines the best of object-oriented and functional programming" languages.

Run Shell Command Programatically

Running a shell" command programmatically means executing a shell" command from within a program, rather than entering the command manually on the command line.

For example, you might want to write a program that runs a shell" command to perform a specific task, such as listing the files in a directory or executing a script. By running the command programmatically, you can automate the task and incorporate it into your program.

To run a shell" command programmatically, you can use a programming language that provides access to the command line, such as Python", Java", or C#. Each language has its own way of running shell" commands, but the basic process is similar: you specify the command and any arguments, and the program executes the command and captures the output. You can then use the output in your program or display it to the user".

How To Run Shell Command In Scala

To execute the shell" command, you must import the sys.process library and then use the available Domain Specific Language (DSL) defined with an exclamation mark (!).

Scala Run Shell Command

The following code shows how to use the ! character run shell" command from Scala:

# Import library
import scala.sys.process._

# Run shell command to create directory in HDFS
val targetPath = "/bigdataetl/data"
s"hdfs dfs -mkdir -p ${targetPath}" !

Apache Spark

Using Apache Spark", you may find that you will also need to perform some operation on files or directories. You can also use the above library as much as possible.

# Delete file from HDFS
s"hdfs dfs -rm /bigdata_etl/temp_file.dat" !

Check example of code how to delete data from HDFS using Spark.

Summary

Overall, running shell" commands programmatically allows you to automate and integrate command-line tasks into your programs, making it easier to perform these tasks without having to manually enter the commands on the command line.

As you can see, thanks to the fact that a method in this programming language can generally be any character, the way we use these functions is very clear and easy to use.

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