wip constructors

internal/cmd/BUILD

@@ -0,0 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["cmd.go"],
+    importpath = "github.com/motiejus/code/undocker/internal/cmd",
+    visibility = ["//src/undocker:__subpackages__"],
+)

internal/cmd/cmd.go

@@ -0,0 +1,20 @@
+package cmd
+
+import (
+	"io"
+	"os"
+)
+
+// BaseCommand provides common fields to all commands.
+type BaseCommand struct {
+	Stdin  io.ReadCloser
+	Stdout io.WriteCloser
+	Stderr io.WriteCloser
+}
+
+// Init initializes BaseCommand with default arguments
+func (b *BaseCommand) Init() {
+	b.Stdin = os.Stdin
+	b.Stdout = os.Stdout
+	b.Stderr = os.Stderr
+}