func LookPath(file string) (string, error)
package main
import (
"fmt"
"log"
"os/exec"
)
func main() {
path, err := exec.LookPath("fortune")
if err != nil {
log.Fatal("installing fortune is in your future")
}
fmt.Printf("fortune is available at %s\n", path)
}
func Command(name string, arg ...string) *Cmd
package main
import (
"bytes"
"fmt"
"log"
"os/exec"
"strings"
)
func main() {
cmd := exec.Command("tr", "a-z", "A-Z")
cmd.Stdin = strings.NewReader("some input")
var out bytes.Buffer
cmd.Stdout = &out
err := cmd.Run()
if err != nil {
log.Fatal(err)
}
fmt.Printf("in all caps: %q\n", out.String())
}
package main
import (
"log"
"os"
"os/exec"
)
func main() {
cmd := exec.Command("prog")
cmd.Env = append(os.Environ(),
"FOO=duplicate_value", // ignored
"FOO=actual_value", // this value is used
)
if err := cmd.Run(); err != nil {
log.Fatal(err)
}
}
func CommandContext(ctx context.Context, name string, arg ...string) *Cmd
package main
import (
"context"
"os/exec"
"time"
)
func main() {
ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
defer cancel()
if err := exec.CommandContext(ctx, "sleep", "5").Run(); err != nil {
// This will fail after 100 milliseconds. The 5 second sleep
// will be interrupted.
}
}
func (c *Cmd) Start() error
package main
import (
"log"
"os/exec"
)
func main() {
cmd := exec.Command("sleep", "5")
err := cmd.Start()
if err != nil {
log.Fatal(err)
}
log.Printf("Waiting for command to finish...")
err = cmd.Wait()
log.Printf("Command finished with error: %v", err)
}
func (c *Cmd) Run() error
package main
import (
"log"
"os/exec"
)
func main() {
cmd := exec.Command("sleep", "1")
log.Printf("Running command and waiting for it to finish...")
err := cmd.Run()
log.Printf("Command finished with error: %v", err)
}
// stdout和stderr分别处理
func main() {
cmd := exec.Command("ls", "-lah")
var stdout, stderr bytes.Buffer
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)
}
func (c *Cmd) Output() ([]byte, error)
package main
import (
"fmt"
"log"
"os/exec"
)
func main() {
out, err := exec.Command("date").Output()
if err != nil {
log.Fatal(err)
}
fmt.Printf("The date is %s\n", out)
}
func (c *Cmd) CombinedOutput() ([]byte, error)
package main
import (
"fmt"
"log"
"os/exec"
)
func main() {
cmd := exec.Command("sh", "-c", "echo stdout; echo 1>&2 stderr")
stdoutStderr, err := cmd.CombinedOutput()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%s\n", stdoutStderr)
}
func (c *Cmd) StdinPipe() (io.WriteCloser, error)
package main
import (
"fmt"
"io"
"log"
"os/exec"
)
func main() {
cmd := exec.Command("cat")
stdin, err := cmd.StdinPipe()
if err != nil {
log.Fatal(err)
}
go func() {
defer stdin.Close()
io.WriteString(stdin, "values written to stdin are passed to cmd's standard input")
}()
out, err := cmd.CombinedOutput()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%s\n", out)
}
func (c *Cmd) StdoutPipe() (io.ReadCloser, error)
package main
import (
"encoding/json"
"fmt"
"log"
"os/exec"
)
func main() {
cmd := exec.Command("echo", "-n", `{"Name": "Bob", "Age": 32}`)
stdout, err := cmd.StdoutPipe()
if err != nil {
log.Fatal(err)
}
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
var person struct {
Name string
Age int
}
if err := json.NewDecoder(stdout).Decode(&person); err != nil {
log.Fatal(err)
}
if err := cmd.Wait(); err != nil {
log.Fatal(err)
}
fmt.Printf("%s is %d years old\n", person.Name, person.Age)
}
func (c *Cmd) StderrPipe() (io.ReadCloser, error)
package main
import (
"fmt"
"io/ioutil"
"log"
"os/exec"
)
func main() {
cmd := exec.Command("sh", "-c", "echo stdout; echo 1>&2 stderr")
stderr, err := cmd.StderrPipe()
if err != nil {
log.Fatal(err)
}
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
slurp, _ := ioutil.ReadAll(stderr)
fmt.Printf("%s\n", slurp)
if err := cmd.Wait(); err != nil {
log.Fatal(err)
}
}