`WriteFile`

A file can be written to disk. With Go we can use a helper module like ioutil to do this easily. For other cases, a NewWriter can be used to write many parts.

With ioutil, we can avoid calling os.Create and bufio.NewWriter. The ioutil.WriteFile method simplifies writing an entire file in one call.

Ioutil example

To begin, we have a string we want to write to a file ("Hello friend"). Then we convert this string to a byte slice so we can pass it to WriteFile.

Info WriteFile receives the target file's path, the bytes we wish to write, and a flag value (zero works fine for testing).

Result The string "Hello friend" is written to the file correctly. The permissions (in Linux) may need to be adjusted first.

package main

import (
    "fmt"
    "io/ioutil"
)

func main() {
    // Get byte data to write to file.
    dataString := "Hello friend"
    dataBytes := []byte(dataString)

    // Use WriteFile to create a file with byte data.
    ioutil.WriteFile("/home/sam/example.txt", dataBytes, 0)
    fmt.Println("DONE")
}
Hello friend

`Os.create`, bufio

We create a new Writer with the bufio.NewWriter function. The file handle we pass to NewWriter must have write access. We must use os.Create (not os.Open) to write a file.

Here We write the string "ABC" to a file on the disk. A new file is created if none exists.

Detail We use flush after writing to the file to ensure all the writes are executed before the program terminates.

package main

import (
    "bufio"
    "os"
)

func main() {
    // Use os.Create to create a file for writing.
    f, _ := os.Create("C:\\programs\\file.txt")

    // Create a new writer.
    w := bufio.NewWriter(f)

    // Write a string to the file.
    w.WriteString("ABC")

    // Flush.
    w.Flush()
}
ABC

With Go we have a language that is well-optimized for writing files to disk. The ioutil module, as always, can reduce the amount of code needed to perform this common task.

WriteFile

Ioutil example

Os.create, bufio

`WriteFile`

`Os.create`, bufio