Go has several useful functions for working with
directories
in the file system. | |
|  package main
|
| import (
"fmt"
"io/fs"
"os"
"path/filepath"
)
|
| func check(e error) {
if e != nil {
panic(e)
}
}
|
| func main() {
|
Create a new sub-directory in the current working
directory. | err := os.Mkdir("subdir", 0755)
check(err)
|
When creating temporary directories, it’s good
practice to
defer
their removal.
os.RemoveAll
will delete a whole directory tree (similarly to
rm -rf
). | defer os.RemoveAll("subdir")
|
Helper function to create a new empty file. | createEmptyFile := func(name string) {
d := []byte("")
check(os.WriteFile(name, d, 0644))
}
|
| createEmptyFile("subdir/file1")
|
We can create a hierarchy of directories, including
parents with
MkdirAll
. This is similar to the
command-line
mkdir -p
. | err = os.MkdirAll("subdir/parent/child", 0755)
check(err)
|
| createEmptyFile("subdir/parent/file2")
createEmptyFile("subdir/parent/file3")
createEmptyFile("subdir/parent/child/file4")
|
ReadDir
lists directory contents, returning a
slice of
os.DirEntry
objects.
| c, err := os.ReadDir("subdir/parent")
check(err)
|
| fmt.Println("Listing subdir/parent")
for _, entry := range c {
fmt.Println(" ", entry.Name(), entry.IsDir())
}
|
Chdir
lets us change the current working directory,
similarly to
cd
.
| err = os.Chdir("subdir/parent/child")
check(err)
|
Now we’ll see the contents of
subdir/parent/child
when listing the
current
directory. | c, err = os.ReadDir(".")
check(err)
|
| fmt.Println("Listing subdir/parent/child")
for _, entry := range c {
fmt.Println(" ", entry.Name(), entry.IsDir())
}
|
cd
back to where we started.
| err = os.Chdir("../../..")
check(err)
|
We can also visit a directory
recursively
,
including all its sub-directories.
WalkDir
accepts
a callback function to handle every file or
directory visited. | fmt.Println("Visiting subdir")
err = filepath.WalkDir("subdir", visit)
}
|
visit
is called for every file or directory found
recursively by
filepath.WalkDir
.
| func visit(path string, d fs.DirEntry, err error) error {
if err != nil {
return err
}
fmt.Println(" ", path, d.IsDir())
return nil
}
|