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Golang program to create a copy of the existing file

Here, we are going to learn how to create a copy of the existing file in Golang (Go Language)?
Submitted by Nidhi, on April 06, 2021 [Last updated : March 04, 2023]

How to create a copy of the existing file in Golang?

Problem Solution:

In this program, we will create a copy of the existing file with the same content using io.Copy() function.

Program/Source Code:

The source code to create a copy of the existing file is given below. The given program is compiled and executed on the ubuntu 18.04 operating system successfully.

Golang code to create a copy of the existing file

// Golang program to create a copy of the
// existing file

package main

import "os"
import "io"
import "fmt"

func main() {
	existingFile, err := os.Open("Sample.txt")

	if err != nil {
		fmt.Println("Unable to open file")
	}

	CopyFile, err := os.Create("Copy.txt")
	if err != nil {
		fmt.Println("Unable to create file")
	}

	len, err := io.Copy(CopyFile, existingFile)
	if err != nil {
		fmt.Println("Unable to copy file")
	}
	fmt.Printf("%d bytes copied successfully", len)

	existingFile.Close()
	CopyFile.Close()
}

Output:

27 bytes copied successfully

Explanation:

In the above program, we declare the package main. The main package is used to tell the Go language compiler that the package must be compiled and produced the executable file. Here, we imported the fmt, os packages then we can use a function related to the fmt and os package.

In the main() function, we opened an existing file "Sample.txt" and then create a new file "Copy.txt"  and copy the content of "Sample.txt" into "Copy.txt". After that, print the total number of bytes copied into the "Copy.txt" file.

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