Add shell example to readme

Signed-off-by: Guillaume J. Charmes <gcharmes@magicleap.com>

README.md

@@ -8,6 +8,8 @@ Pty is a Go package for using unix pseudo-terminals.
 
 ## Example
 
+### Command
+
 ```go
 package main
 
@@ -34,3 +36,65 @@ func main() {
 	io.Copy(os.Stdout, f)
 }
 ```
+
+### Shell
+
+```go
+package main
+
+import (
+        "io"
+        "log"
+        "os"
+        "os/exec"
+        "os/signal"
+        "syscall"
+
+        "github.com/kr/pty"
+        "golang.org/x/crypto/ssh/terminal"
+)
+
+func test() error {
+        // Create arbitrary command.
+        c := exec.Command("bash")
+
+        // Start the command with a pty.
+        ptmx, err := pty.Start(c)
+        if err != nil {
+                return err
+        }
+        // Make sure to close the pty at the end.
+        defer func() { _ = ptmx.Close() }() // Best effort.
+
+        // Handle pty size.
+        ch := make(chan os.Signal, 1)
+        signal.Notify(ch, syscall.SIGWINCH)
+        go func() {
+                for range ch {
+                        if err := pty.InheritSize(os.Stdin, ptmx); err != nil {
+                                log.Printf("error resizing pty: %s", err)
+                        }
+                }
+        }()
+        ch <- syscall.SIGWINCH // Initial resize.
+
+        // Set stdin in raw mode.
+        oldState, err := terminal.MakeRaw(int(os.Stdin.Fd()))
+        if err != nil {
+                panic(err)
+        }
+        defer func() { _ = terminal.Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
+
+        // Copy stdin to the pty and the pty to stdout.
+        go func() { _, _ = io.Copy(ptmx, os.Stdin) }()
+        _, _ = io.Copy(os.Stdout, ptmx)
+
+        return nil
+}
+
+func main() {
+        if err := test(); err != nil {
+                log.Fatal(err)
+        }
+}
+```