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Table of contents
1.
Introduction 
2.
How to get Command Arguments in Go
2.1.
Flag Package
2.1.1.
Example
2.2.
OS Package
2.2.1.
Example 1
2.2.2.
Example 2
3.
FAQs
4.
Key takeaways
Last Updated: Mar 27, 2024

Go Command Arguments

Author Shivam Verma
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Introduction 

When we want to run a program on the terminal, we have to type a command in this window that takes the text. We can also put some more text after this command. Every word or thing that is separated by spaces after the command is called a command argument.

Command arguments are a way to supply additional information to a program when it is started. We generally use the command argument when we need to execute a program with some arguments. The Go program can receive every argument that is passed from the console, and it can be used as an input.

How to get Command Arguments in Go

There are two ways to get arguments from the command line in the Go programming language.

Flag Package

The first way to get Command Arguments is via flag package.

In Go language, we have a package named as flag to parse command arguments. Once we have declared our flags, we call flag.Parse() to execute the command-line parsing.

Example

package main
import (
  "flag"
  "fmt"
)
func main(){
  flag.Parse()     // to get the command arguments 
  arg1 := flag.Arg(0) // returns first argument
  arg2 := flag.Arg(1)  // returns second argument
  fmt.Println("The first argument " + arg1)
  fmt.Println("The second argument " + arg2)
}

Output:

OS Package

The second way to get Command Arguments is via the os package.

In Go language, we have a package named as os package containing an array called "Args". Args is an array of strings containing all the go command arguments passed.

The os.Args returns an array of command-line parameters. The first parameter of os.Args is the path of the program.

Example 1

package main
import (
  "os"
  "fmt"
)
func main(){
  argLength:=len(os.Args)
  fmt.Println("Arg length is ",argLength)
  var str, arg string  
    for i:=1;i<argLength;i++{  
        str+=arg+os.Args[i]+" "  
    }  
    fmt.Println(str)     
}

Output: 

Example 2

package main
import (
  "os"
  "fmt"
)
func main(){
  argWithpath:=os.Args //returns all arguments including path  
  programName:=os.Args[0]
  argwithoutpath:=os.Args[1:]   //returns all arguments after path  
  arg2:=os.Args[2]   //returns second argument only   
  arg3:=os.Args[3]    //returns third argument only 
  fmt.Println(argWithpath)  
  fmt.Println(programName)  
  fmt.Println(argwithoutpath) 
  fmt.Println(arg2)  
  fmt.Println(arg3)   
}

Output: 

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FAQs

  1. How do we implement command-line arguments in Go?
    Ans: Command arguments are a way to supply additional information to a program when it is started. Similarly, In Go language, we use this technique to pass the arguments at the run time of a program. 
    In Go language, we have a package named as os package containing an array of strings called "Args". Args contain all the go command arguments passed.
     
  2. How do we check if a string is empty in Golang?
    Ans: Using the len() method, we can get the length of the string, and if it is equal to 0, then the string is empty.
     
  3. What are command arguments?
    Ans: Command arguments are nothing but simply arguments that are specified after the program's name in the system's command line. These argument values are passed on to our program during the program's execution.

Key takeaways

In this article, we have extensively discussed the command arguments in the Go programming language. We also discussed how we could get Command Arguments in the Go language.

We hope that this blog has helped you enhance your knowledge regarding Go command arguments and if you would like to learn more, check out our article on C command-line arguments. You can read other C language articles by clicking here. Do upvote our blog to help ninjas grow. Happy Coding!

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