github.com/ccccaoqing/test@v0.0.0-20220510085219-3985d23445c0/src/os/exec/example_test.go (about)

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package exec_test
     6  
     7  import (
     8  	"bytes"
     9  	"encoding/json"
    10  	"fmt"
    11  	"log"
    12  	"os/exec"
    13  	"strings"
    14  )
    15  
    16  func ExampleLookPath() {
    17  	path, err := exec.LookPath("fortune")
    18  	if err != nil {
    19  		log.Fatal("installing fortune is in your future")
    20  	}
    21  	fmt.Printf("fortune is available at %s\n", path)
    22  }
    23  
    24  func ExampleCommand() {
    25  	cmd := exec.Command("tr", "a-z", "A-Z")
    26  	cmd.Stdin = strings.NewReader("some input")
    27  	var out bytes.Buffer
    28  	cmd.Stdout = &out
    29  	err := cmd.Run()
    30  	if err != nil {
    31  		log.Fatal(err)
    32  	}
    33  	fmt.Printf("in all caps: %q\n", out.String())
    34  }
    35  
    36  func ExampleCmd_Output() {
    37  	out, err := exec.Command("date").Output()
    38  	if err != nil {
    39  		log.Fatal(err)
    40  	}
    41  	fmt.Printf("The date is %s\n", out)
    42  }
    43  
    44  func ExampleCmd_Start() {
    45  	cmd := exec.Command("sleep", "5")
    46  	err := cmd.Start()
    47  	if err != nil {
    48  		log.Fatal(err)
    49  	}
    50  	log.Printf("Waiting for command to finish...")
    51  	err = cmd.Wait()
    52  	log.Printf("Command finished with error: %v", err)
    53  }
    54  
    55  func ExampleCmd_StdoutPipe() {
    56  	cmd := exec.Command("echo", "-n", `{"Name": "Bob", "Age": 32}`)
    57  	stdout, err := cmd.StdoutPipe()
    58  	if err != nil {
    59  		log.Fatal(err)
    60  	}
    61  	if err := cmd.Start(); err != nil {
    62  		log.Fatal(err)
    63  	}
    64  	var person struct {
    65  		Name string
    66  		Age  int
    67  	}
    68  	if err := json.NewDecoder(stdout).Decode(&person); err != nil {
    69  		log.Fatal(err)
    70  	}
    71  	if err := cmd.Wait(); err != nil {
    72  		log.Fatal(err)
    73  	}
    74  	fmt.Printf("%s is %d years old\n", person.Name, person.Age)
    75  }