golang执行Linux shell命令完整场景下的使用方法

golang执行Linux shell命令完整场景下的使用方法

1. 执行命令并获得输出结果

CombinedOutput()

执行程序返回 standard output and standard error

func main() { cmd := exec.Command("ls", "-lah") out, err := cmd.CombinedOutput() if err != nil { log.Fatalf("cmd.Run() failed with %s\n", err) } fmt.Printf("combined out:\n%s\n", string(out))}

Output()

执行程序返回standard output

func main() { out, err := exec.Command("date").Output() if err != nil { log.Fatal(err) } fmt.Printf("The date is %s\n", out)}

2. 将stdout和stderr分别处理

用buffer接受输出

func main() { cmd := exec.Command("ls", "-lah") var stdin, stdout, stderr bytes.Buffer cmd.Stdin = &stdin cmd.Stdout = &stdout cmd.Stderr = &stderr err := cmd.Run() if err != nil { log.Fatalf("cmd.Run() failed with %s\n", err) } outStr, errStr := string(stdout.Bytes()), string(stderr.Bytes()) fmt.Printf("out:\n%s\nerr:\n%s\n", outStr, errStr)}

直接打印到屏幕

func main() { cmd := exec.Command("ls", "-lah") cmd.Stdout = os.Stdout cmd.Stderr = os.Stdout err := cmd.Run() if err != nil { log.Fatalf("cmd.Run() failed with %s\n", err) }}

3. 异步执行命令

cmd.Run() 阻塞等待命令执行结束 cmd.Start() 不会等待命令完成

package mainimport ( "bytes" "fmt" "io" "log" "os" "os/exec")func main() { var stdoutBuf, stderrBuf bytes.Buffer cmd := exec.Command("bash", "-c", "for i in 1 2 3 4;do echo $i;sleep 2;done") stdoutIn, _ := cmd.StdoutPipe() stderrIn, _ := cmd.StderrPipe() var errStdout, errStderr error stdout := io.MultiWriter(os.Stdout, &stdoutBuf) stderr := io.MultiWriter(os.Stderr, &stderrBuf) err := cmd.Start() if err != nil { log.Fatalf("cmd.Start() failed with '%s'\n", err) } go func() { _, errStdout = io.Copy(stdout, stdoutIn) }() go func() { _, errStderr = io.Copy(stderr, stderrIn) }() err = cmd.Wait() if err != nil { log.Fatalf("cmd.Run() failed with %s\n", err) } if errStdout != nil || errStderr != nil { log.Fatal("failed to capture stdout or stderr\n") } outStr, errStr := string(stdoutBuf.Bytes()), string(stderrBuf.Bytes()) fmt.Printf("\nout:\n%s\nerr:\n%s\n", outStr, errStr)}

4. 执行时带上环境变量

func main() { cmd := exec.Command("bash", "-c", "programToExecute") additionalEnv := "programToExecute=ls" newEnv := append(os.Environ(), additionalEnv) cmd.Env = newEnv out, err := cmd.CombinedOutput() if err != nil { log.Fatalf("cmd.Run() failed with %s\n", err) } fmt.Printf("%s", out)}

5. 预先检查命令是否存在

func checkLsExists() { path, err := exec.LookPath("ls") if err != nil { fmt.Printf("didn't find 'ls' executable\n") } else { fmt.Printf("'ls' executable is in '%s'\n", path) }}

6. 两个命令依次执行，管道通信

func main() { c1 := exec.Command("ls") c2 := exec.Command("wc", "-l") r, w := io.Pipe() c1.Stdout = w c2.Stdin = r var b2 bytes.Buffer c2.Stdout = &b2 c1.Start() c2.Start() c1.Wait() w.Close() c2.Wait() io.Copy(os.Stdout, &b2)}

或者

func main() { c1 := exec.Command("ls") c2 := exec.Command("wc", "-l") c2.Stdin, _ = c1.StdoutPipe() c2.Stdout = os.Stdout _ = c2.Start() _ = c1.Run() _ = c2.Wait()}

反正下面这样是不行的

func main() { c := exec.Command("ls", "|", "wc", "-l") c.Stdout = os.Stdout _ = c.Run()}

不嫌丑可以用bash -c

func main() { cmd := "cat /proc/cpuinfo | egrep '^model name' | uniq | awk '{print substr($0, index($0,$4))}'" out, err := exec.Command("bash", "-c", cmd).Output() if err != nil { fmt.Printf("Failed to execute command: %s", cmd) } fmt.Println(string(out))}

7. 按行读取输出内容

func main() { cmd := exec.Command("ls", "-la") stdout, _ := cmd.StdoutPipe() cmd.Start() reader := bufio.NewReader(stdout) for { line, err := reader.ReadString('\n') line = strings.TrimSpace(line) if err != nil || io.EOF == err { break } log.Println(line) } cmd.Wait()}

8. 获得exit code

func RunCommand(name string, args ...string) (stdout string, stderr string, exitCode int) { log.Println("run command:", name, args) var outbuf, errbuf bytes.Buffer cmd := exec.Command(name, args...) cmd.Stdout = &outbuf cmd.Stderr = &errbuf err := cmd.Run() stdout = outbuf.String() stderr = errbuf.String() if err != nil { // try to get the exit code if exitError, ok := err.(*exec.ExitError); ok { ws := exitError.Sys().(syscall.WaitStatus) exitCode = ws.ExitStatus() } else { // This will happen (in OSX) if `name` is not available in $PATH, // in this situation, exit code could not be get, and stderr will be // empty string very likely, so we use the default fail code, and format err // to string and set to stderr log.Printf("Could not get exit code for failed program: %v, %v", name, args) exitCode = defaultFailedCode if stderr == "" { stderr = err.Error() } } } else { // success, exitCode should be 0 if go is ok ws := cmd.ProcessState.Sys().(syscall.WaitStatus) exitCode = ws.ExitStatus() } log.Printf("command result, stdout: %v, stderr: %v, exitCode: %v", stdout, stderr, exitCode) return}

参考链接：

​​https://saucer-man.com/backend_development/571.html​​

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