121 lines
2.3 KiB
Go
121 lines
2.3 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package os_test
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import (
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"fmt"
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"log"
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"os"
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"time"
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)
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func ExampleOpenFile() {
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f, err := os.OpenFile("notes.txt", os.O_RDWR|os.O_CREATE, 0755)
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if err != nil {
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log.Fatal(err)
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}
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if err := f.Close(); err != nil {
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log.Fatal(err)
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}
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}
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func ExampleOpenFile_append() {
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// If the file doesn't exist, create it, or append to the file
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f, err := os.OpenFile("access.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
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if err != nil {
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log.Fatal(err)
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}
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if _, err := f.Write([]byte("appended some data\n")); err != nil {
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log.Fatal(err)
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}
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if err := f.Close(); err != nil {
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log.Fatal(err)
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}
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}
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func ExampleChmod() {
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if err := os.Chmod("some-filename", 0644); err != nil {
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log.Fatal(err)
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}
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}
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func ExampleChtimes() {
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mtime := time.Date(2006, time.February, 1, 3, 4, 5, 0, time.UTC)
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atime := time.Date(2007, time.March, 2, 4, 5, 6, 0, time.UTC)
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if err := os.Chtimes("some-filename", atime, mtime); err != nil {
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log.Fatal(err)
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}
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}
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func ExampleFileMode() {
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fi, err := os.Lstat("some-filename")
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if err != nil {
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log.Fatal(err)
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}
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switch mode := fi.Mode(); {
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case mode.IsRegular():
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fmt.Println("regular file")
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case mode.IsDir():
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fmt.Println("directory")
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case mode&os.ModeSymlink != 0:
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fmt.Println("symbolic link")
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case mode&os.ModeNamedPipe != 0:
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fmt.Println("named pipe")
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}
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}
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func ExampleIsNotExist() {
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filename := "a-nonexistent-file"
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if _, err := os.Stat(filename); os.IsNotExist(err) {
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fmt.Printf("file does not exist")
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}
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// Output:
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// file does not exist
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}
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func init() {
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os.Setenv("USER", "gopher")
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os.Setenv("HOME", "/usr/gopher")
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os.Unsetenv("GOPATH")
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}
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func ExampleExpandEnv() {
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fmt.Println(os.ExpandEnv("$USER lives in ${HOME}."))
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// Output:
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// gopher lives in /usr/gopher.
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}
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func ExampleLookupEnv() {
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show := func(key string) {
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val, ok := os.LookupEnv(key)
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if !ok {
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fmt.Printf("%s not set\n", key)
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} else {
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fmt.Printf("%s=%s\n", key, val)
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}
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}
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show("USER")
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show("GOPATH")
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// Output:
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// USER=gopher
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// GOPATH not set
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}
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func ExampleGetenv() {
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fmt.Printf("%s lives in %s.\n", os.Getenv("USER"), os.Getenv("HOME"))
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// Output:
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// gopher lives in /usr/gopher.
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}
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func ExampleUnsetenv() {
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os.Setenv("TMPDIR", "/my/tmp")
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defer os.Unsetenv("TMPDIR")
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}
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