How to remove all contents of a directory using Golang?

I'm new to Go and can't seem to find a way to delete all the contents of a directory when I don't know the contents.

I've tried:

os.RemoveAll("/tmp/*")
os.Remove("/tmp/*")

but get remove *: no such file or directory or invalid argument.

And of course if you do:

os.RemoveAll("/tmp/")

it deletes the tmp directory as well. Which is not what I want.

Simply do:

os.RemoveAll("/tmp/")
os.MkdirAll("/tmp/",FileMode)

Write a simple RemoveContents function. For example,

package main
import (
"fmt"
"os"
"path/filepath"
"strings"
)
func RemoveContents(dir string) error {
d, err := os.Open(dir)
if err != nil {
return err
}
defer d.Close()
names, err := d.Readdirnames(-1)
if err != nil {
return err
}
for _, name := range names {
err = os.RemoveAll(filepath.Join(dir, name))
if err != nil {
return err
}
}
return nil
}
func main() {
dir := strings.TrimSuffix(filepath.Base(os.Args[0]), filepath.Ext(os.Args[0]))
dir = filepath.Join(os.TempDir(), dir)
dirs := filepath.Join(dir, `tmpdir`)
err := os.MkdirAll(dirs, 0777)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
file := filepath.Join(dir, `tmpfile`)
f, err := os.Create(file)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
f.Close()
file = filepath.Join(dirs, `tmpfile`)
f, err = os.Create(file)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
f.Close()
err = RemoveContents(dir)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
}

Just use ioutil.ReadDir to get a slice of os.FileInfo types, then iterate through and remove each child item using os.RemoveAll.

package main
import (
"io/ioutil"
"os"
"path"
)
func main() {
dir, err := ioutil.ReadDir("/tmp")
for _, d := range dir {
os.RemoveAll(path.Join([]string{"tmp", d.Name()}...))
}
}

That way, you are removing only all the child items and not the parent /tmp folder itself.

I have used this pattern many times before (e.g. test logs, etc.).

You could use filepath.Glob() to get a slice of the contents of the folder, then delete everything it returns. This allows you to use /tmp/* to indicate what you want to delete, and could also be used to delete /tmp/*.go, or /tmp/*/*.go, etc.

package main
import (
"log"
"os"
"path/filepath"
)
func RemoveGlob(path string) (err error) {
contents, err := filepath.Glob(path)
if err != nil {
return
}
for _, item := range contents {
err = os.RemoveAll(item)
if err != nil {
return
}
}
return
}    
func main() {
err := RemoveGlob("/tmp/*")
if err != nil {
log.Fatalf("Error removing files: %+v", err)
}
}

func RemoveContents(dir string) error {
files, err := filepath.Glob(filepath.Join(dir, "*"))
if err != nil {
return err
}
for _, file := range files {
err = os.RemoveAll(file)
if err != nil {
return err
}
}
return nil
}