-
Create directory
package main
import (
"log"
"os"
)
func main() {
_, err := os.Stat("text")
if os.IsNotExist(err) {
errDir := os.MkdirAll("text", 0755)
if errDir != nil {
log.Fatal(err)
}
}
}
Output :
PS C:\GO_Language\file> go run create.go
-
Rename a file
package main
import (
"log"
"os"
)
func main() {
oldName := "test.txt"
newName := "testing.txt"
err := os.Rename(oldName, newName)
if err != nil {
log.Fatal(err)
}
}
Output :
PS C:\GO_Language\file> go run rename.go
-
Copy file at the specified location
package main
import (
"io"
"log"
"os"
)
func main() {
sourceFile, err := os.Open("C:/GO_Language/file/test.txt")
if err != nil {
log.Fatal(err)
}
defer sourceFile.Close()
// Create new file
newFile, err := os.Create("C:/GO_Language/test.txt ")
if err != nil {
log.Fatal(err)
}
defer newFile.Close()
bytesCopied, err := io.Copy(newFile, sourceFile)
if err != nil {
log.Fatal(err)
}
log.Printf("Copied %d bytes.", bytesCopied)
}
Output :
PS C:\GO_Language\file> go run f1.go
2022/08/20 15:39:48 Copied 59 bytes.
-
Move a File
package main
import (
"log"
"os"
)
func main() {
oldLocation := "C:/GO_Language/test.txt"
newLocation := "C:/GO_Language/file/test.txt"
err := os.Rename(oldLocation, newLocation)
if err != nil {
log.Fatal(err)
}
}
Output :
PS C:\GO_Language\file> go run move.go
-
Getting Metadata of a file
package main
import (
"fmt"
"log"
"os"
)
func main() {
fileStat, err := os.Stat("test.txt")
if err != nil {
log.Fatal(err)
}
fmt.Println("File Name:", fileStat.Name())
fmt.Println("Size:", fileStat.Size())
fmt.Println("Permissions:", fileStat.Mode())
fmt.Println("Last Modified:", fileStat.ModTime())
fmt.Println("Is Directory: ", fileStat.IsDir())
}
Output :
PS C:\GO_Language\file> go run matadata.go
File Name: test.txt
Size: 59
Permissions: -rw-rw-rw-
Last Modified: 2022-08-20 15:39:48.8907731 +0530 IST
Is Directory: false
-
Deleting a specific file
package main
import (
"log"
"os"
)
func main() {
err := os.Remove("C:/GO_Language/test.txt ")
if err != nil {
log.Fatal(err)
}
}
Output :
PS C:\GO_Language\file> go run delete.go
-
Read a text file character by character
package main
import (
"bufio"
"fmt"
"io/ioutil"
"os"
"strings"
)
func main() {
filename := "test.txt"
filebuffer, err := ioutil.ReadFile(filename)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
inputdata := string(filebuffer)
data := bufio.NewScanner(strings.NewReader(inputdata))
data.Split(bufio.ScanRunes)
for data.Scan() {
fmt.Print(data.Text())
}
}
Output :
PS C:\GO_Language\file> go run readchar.go
Sandeep
Ramesh
Shankar
Mohan
dhanaji
Rajya
Sohel
-
Truncate File Content
package main
import (
"log"
"os"
)
func main() {
err := os.Truncate("test.txt", 100)
if err != nil {
log.Fatal(err)
}
}
PS C:\GO_Language\file> go run truncate.go
-
Append Content in a Text File
package main
import (
"fmt"
"os"
)
func main() {
msg := "Add this content at end"
fname := "test.txt"
f, err := os.OpenFile(fname, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0660)
if err != nil {
fmt.Println(err)
os.Exit(-1)
}
defer f.Close()
fmt.Fprintf(f, "%s\n", msg)
}
Output :
PS C:\GO_Language\file> go run append.go
-
Change file permission, ownership, and timestamps
package main
import (
"log"
"os"
"time"
)
func main() {
_, err := os.Stat("test.txt")
if err != nil {
if os.IsNotExist(err) {
log.Fatal("File does not exist.")
}
}
log.Println("File exist.")
// Change permissions Linux.
err = os.Chmod("test.txt", 0777)
if err != nil {
log.Println(err)
}
// Change file ownership.
err = os.Chown("test.txt", os.Getuid(), os.Getgid())
if err != nil {
log.Println(err)
}
// Change file timestamps.
addOneDayFromNow := time.Now().Add(24 * time.Hour)
lastAccessTime := addOneDayFromNow
lastModifyTime := addOneDayFromNow
err = os.Chtimes("test.txt", lastAccessTime, lastModifyTime)
if err != nil {
log.Println(err)
}
}
Output :
PS C:\GO_Language\file> go run change.go
2022/08/20 16:55:42 File exist.
2022/08/20 16:55:42 chown test.txt: not supported by windows
-
Compress a list of files into a ZIP file
package main
import (
"archive/zip"
"fmt"
"io"
"log"
"os"
)
func appendFiles(fname string, zipw *zip.Writer) error {
file, err := os.Open(fname)
if err != nil {
return fmt.Errorf("Failed to open %s: %s", fname, err)
}
defer file.Close()
wr, err := zipw.Create(fname)
if err != nil {
msg := "Failed to create entry for %s in zip file: %s"
return fmt.Errorf(msg, fname, err)
}
if _, err := io.Copy(wr, file); err != nil {
return fmt.Errorf("Failed to write %s to zip: %s", fname, err)
}
return nil
}
func main() {
flags := os.O_WRONLY | os.O_CREATE | os.O_TRUNC
file, err := os.OpenFile("test.zip", flags, 0644)
if err != nil {
log.Fatalf("Failed to open zip for writing: %s", err)
}
defer file.Close()
var files = []string{"test1.txt", "test2.txt", "test3.txt"}
zipw := zip.NewWriter(file)
defer zipw.Close()
for _, filename := range files {
if err := appendFiles(filename, zipw); err != nil {
log.Fatalf("Failed to add file %s to zip: %s", fname, err)
}
}
}
Output :
PS C:\GO_Language\file> go run compress.go
-
Extract or Unzip
package main
import (
"archive/zip"
"io"
"log"
"os"
"path/filepath"
)
func main() {
zipReader, _ := zip.OpenReader("test.zip")
for _, file := range zipReader.Reader.File {
zippedFile, err := file.Open()
if err != nil {
log.Fatal(err)
}
defer zippedFile.Close()
tDir := "./"
extractedFilePath := filepath.Join(
tDir,
file.Name,
)
if file.FileInfo().IsDir() {
log.Println("Directory Created:", extractedFilePath)
os.MkdirAll(extractedFilePath, file.Mode())
} else {
log.Println("File extracted:", file.Name)
opFile, err := os.OpenFile(
extractedFilePath,
os.O_WRONLY|os.O_CREATE|os.O_TRUNC,
file.Mode(),
)
if err != nil {
log.Fatal(err)
}
defer opFile.Close()
_, err = io.Copy(opFile, zippedFile)
if err != nil {
log.Fatal(err)
}
}
}
}
Output :
PS C:\GO_Language\file> go run extract.go
2022/08/20 17:11:43 File extracted: test1.txt
2022/08/20 17:11:43 File extracted: test2.txt
2022/08/20 17:11:43 File extracted: test3.txt
