Exercise 5: File Handling in Go

Why Work with Files in Go?

File handling is essential for saving, retrieving, and processing data efficiently in Go applications.

Reading a File in Go

We use the `os.ReadFile()` function to read the contents of a file.

package main

import (
    "fmt"
    "os"
)

func main() {
    content, err := os.ReadFile("example.txt")
    if err != nil {
        fmt.Println("Error reading the file:", err)
        return
    }
    fmt.Println(string(content))
}

Writing to a File in Go

To write to a file, we use `os.WriteFile()`.

package main

import (
    "fmt"
    "os"
)

func main() {
    text := []byte("Hello, Go!")
    err := os.WriteFile("example.txt", text, 0644)
    if err != nil {
        fmt.Println("Error writing to file:", err)
        return
    }
    fmt.Println("File written successfully!")
}

Exercise Instructions

• Create a file files.go.
• Write a Go program that creates a file, writes text to it, and then reads it back.
• Display the file contents in the console.

Expected Output

File written successfully!
Hello, Go!

Best Practices for File Handling in Go

• ✅ Always check for errors when reading or writing files.
• ✅ Use `defer file.Close()` to properly close file handles.
• ✅ Set appropriate file permissions to avoid security risks.
• ✅ Use `bufio` for large files to improve performance.

📚 Learn more about file handling in Go:

Official Go Documentation