os/exec: add examples for CombinedOutput, StdinPipe, StderrPipe

Updates #16360.

Adds examples for:
+ CombinedOutput
+ StdinPipe
+ StderrPipe

Change-Id: I19293e64b34ed9268da00e0519173a73bfbc2c10
Reviewed-on: https://go-review.googlesource.com/29150
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

diff --git a/src/os/exec/example_test.go b/src/os/exec/example_test.go
index 55eaac8abcede261af83287f55648a9d730c68a7..a38e2889e6470b00c903dee8cac946ac9f451528 100644 (file)
--- a/src/os/exec/example_test.go
+++ b/src/os/exec/example_test.go
@@ -8,6 +8,8 @@ import (
        "bytes"
        "encoding/json"
        "fmt"
+       "io"
+       "io/ioutil"
        "log"
        "os/exec"
        "strings"
@@ -73,3 +75,51 @@ func ExampleCmd_StdoutPipe() {
        }
        fmt.Printf("%s is %d years old\n", person.Name, person.Age)
 }
+
+func ExampleCmd_StdinPipe() {
+       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 ExampleCmd_StderrPipe() {
+       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)
+       }
+}
+
+func ExampleCmd_CombinedOutput() {
+       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)
+}