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