diff --git a/ui/build/exec.go b/ui/build/exec.go
new file mode 100644
index 0000000..4c45c50
--- /dev/null
+++ b/ui/build/exec.go
@@ -0,0 +1,107 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package build
+
+import (
+	"os/exec"
+)
+
+// Cmd is a wrapper of os/exec.Cmd that integrates with the build context for
+// logging, the config's Environment for simpler environment modification, and
+// implements hooks for sandboxing
+type Cmd struct {
+	*exec.Cmd
+
+	Environment *Environment
+	Sandbox     Sandbox
+
+	ctx    Context
+	config Config
+	name   string
+}
+
+func Command(ctx Context, config Config, name string, executable string, args ...string) *Cmd {
+	ret := &Cmd{
+		Cmd:         exec.CommandContext(ctx.Context, executable, args...),
+		Environment: config.Environment().Copy(),
+		Sandbox:     noSandbox,
+
+		ctx:    ctx,
+		config: config,
+		name:   name,
+	}
+
+	return ret
+}
+
+func (c *Cmd) prepare() {
+	if c.Env == nil {
+		c.Env = c.Environment.Environ()
+	}
+	if c.sandboxSupported() {
+		c.wrapSandbox()
+	}
+
+	c.ctx.Verboseln(c.Path, c.Args)
+}
+
+func (c *Cmd) Start() error {
+	c.prepare()
+	return c.Cmd.Start()
+}
+
+func (c *Cmd) Run() error {
+	c.prepare()
+	return c.Cmd.Run()
+}
+
+func (c *Cmd) Output() ([]byte, error) {
+	c.prepare()
+	return c.Cmd.Output()
+}
+
+func (c *Cmd) CombinedOutput() ([]byte, error) {
+	c.prepare()
+	return c.Cmd.CombinedOutput()
+}
+
+// StartOrFatal is equivalent to Start, but handles the error with a call to ctx.Fatal
+func (c *Cmd) StartOrFatal() {
+	if err := c.Start(); err != nil {
+		c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
+	}
+}
+
+// RunOrFatal is equivalent to Run, but handles the error with a call to ctx.Fatal
+func (c *Cmd) RunOrFatal() {
+	if err := c.Run(); err != nil {
+		if e, ok := err.(*exec.ExitError); ok {
+			c.ctx.Fatalf("%s failed with: %v", c.name, e.ProcessState.String())
+		} else {
+			c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
+		}
+	}
+}
+
+// WaitOrFatal is equivalent to Wait, but handles the error with a call to ctx.Fatal
+func (c *Cmd) WaitOrFatal() {
+	if err := c.Wait(); err != nil {
+		if e, ok := err.(*exec.ExitError); ok {
+			c.ctx.Fatalf("%s failed with: %v", c.name, e.ProcessState.String())
+		} else {
+			c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
+		}
+	}
+}