When you need to write the same output into more than one target, there is a helping hand available in the built-in package. This recipe shows how to implement writing simultaneously into multiple targets.

Create the multiwr.go file with the following content:

        package main

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

        func main() {

          buf := bytes.NewBuffer([]byte{})
          f, err := os.OpenFile("sample.txt", os.O_CREATE|os.O_RDWR,
                                os.ModePerm)
          if err != nil {
            panic(err)
          }
          wr := io.MultiWriter(buf, f)
          _, err = io.WriteString(wr, "Hello, Go is awesome!")
          if err != nil {
            panic(err)
          }

          fmt.Println("Content of buffer: " + buf.String())
        }

output:

sangam:golang-daily sangam$ go run multiwr.go
Content of buffer: Hello, Go is awesome!
sangam:golang-daily sangam$

Check the content of the created file: sample.txt#

      Hello, Go is awesome!

How it works...#

The io package contains the MultiWriter function with variadic parameters of Writers.
When the Write method on the Writer is called, then the data is written to all underlying Writers.

writing to multiple writers at once

Create the multiwr.go file with the following content:

Check the content of the created file: sample.txt#

How it works...#

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