breakup v2 documentation

docs/v2/examples/exit-codes.md

@@ -0,0 +1,38 @@
+Calling `App.Run` will not automatically call `os.Exit`, which means that by
+default the exit code will "fall through" to being `0`.  An explicit exit code
+may be set by returning a non-nil error that fulfills `cli.ExitCoder`, *or* a
+`cli.MultiError` that includes an error that fulfills `cli.ExitCoder`, e.g.:
+<!-- {
+  "error": "Ginger croutons are not in the soup"
+} -->
+```go
+package main
+
+import (
+	"log"
+	"os"
+
+	"github.com/urfave/cli/v2"
+)
+
+func main() {
+	app := &cli.App{
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:  "ginger-crouton",
+				Usage: "is it in the soup?",
+			},
+		},
+		Action: func(ctx *cli.Context) error {
+			if !ctx.Bool("ginger-crouton") {
+				return cli.Exit("Ginger croutons are not in the soup", 86)
+			}
+			return nil
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		log.Fatal(err)
+	}
+}
+```