Exemple lecture fichier texte

package main
 
import (
        "bufio"
        "fmt"
        "os"
)
 
func main() {
 
        file, err := os.Open("input.txt")
        if err != nil {
                panic(err)
        }
        defer func() {
                if err := file.Close(); err != nil {
                        panic(err)
                }
        }()
        scanner := bufio.NewScanner(file)
 
        // Iterate over each line
        for scanner.Scan() {
                line := scanner.Text()
                fmt.Println(line)
        }
 
}

Exemple d'écriture texte

func write_file(filename string, data string) {
	file, err := os.Create(filename)
	if err != nil {
		panic(err)
	}
	defer func() {
		if err := file.Close(); err != nil {
			panic(err)
		}
	}()
	_, err = file.WriteString(data)
	if err != nil {
		panic(err)
	}
 
}

Exemple de copie de fichier

Voir : https://opensource.com/article/18/6/copying-files-go

func copyFile(src, dest string) {
	input, err := ioutil.ReadFile(src)
	if err != nil {
		panic(err)
	}
 
	err = ioutil.WriteFile(dest, input, 0644)
	if err != nil {
		fmt.Println("Error creating", dest)
		panic(err)
	}
}

Fichier droits POSIX octal mode

Voir aussi :

• https://golang.howtos.io/using-the-os-filemode-type-in-go/

	file, err := os.Lstat("/tmp/plop")
	if err != nil {
		panic(err)
	}
	mode := file.Mode()
	fmt.Printf("%s\n", mode)
	fmt.Printf("%o\n", mode)

Exemple lecture fichier CSV

package main
 
import (
        "encoding/csv"
        "fmt"
        "log"
        "os"
        "regexp"
)
 
func IsMatchingRegex(s string, regex string) bool {
        return regexp.MustCompile(regex).MatchString(s)
}
 
func main() {
        file, err := os.Open("data.csv")
        if err != nil {
                log.Fatal(err)
        }
        defer file.Close()
 
        // Read all records from the CSV file
        reader := csv.NewReader(file)
        reader.Comma = ';'
        records, err := reader.ReadAll()
        if err != nil {
                log.Fatal(err)
        }
 
 
        for _, record := range records[1:] {
                if IsMatchingRegex(record[0], "^#") {
                        continue
                }
 
                fmt.Println(record[0])
                fmt.Println(record[1])
        }
}

Exemple de calcul de hash d'un fichier

package main
 
import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"io"
	"os"
)
 
func hashFile(filePath string) (string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return "", fmt.Errorf("failed to open file: %w", err)
	}
	defer file.Close()
 
	hasher := sha256.New()
	if _, err := io.Copy(hasher, file); err != nil {
		return "", fmt.Errorf("failed to hash file: %w", err)
	}
 
	return hex.EncodeToString(hasher.Sum(nil)), nil
}
 
func main() {
	hash, err := hashFile("/tmp/plop")
	if err != nil {
		panic(err)
	}
 
	fmt.Println(hash)
}