Golang : Copy file

Here’s an example to copy a file named “input.txt” to another file named “output.txt”.

Copying files can be done in several ways in Go. The example below is the easiest :

 package main

 import (
 "io"
 "fmt"
 "os"
 )

 func main () {
 // open files r and w
 r, err := os.Open("input.txt")
 if err != nil {
 panic(err)
 }
 defer r.Close()

 w, err := os.Create("output.txt")
 if err != nil {
 panic(err)
 }
 defer w.Close()

 // do the actual work
 n, err := io.Copy(w, r)
 if err != nil {
 panic(err)
 }

 fmt.Printf("Copied %v bytes\n", n)
 }

With the file input.txt in the same directory,

execute >go run copyfile.go and output will something similar to this

Copied 561 bytes