Refactor almost complete

19 files changed, 639 insertions, 954 deletions

diff --git a/cmd/cmd.go b/cmd/cmd.go
index 945e945..3358015 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -1,5 +1,5 @@
 /*
- * cmd.go - Main interface to cmd package (running, Cmd and Flag structs, etc)
+ * cmd.go - Main interface to cmd package (Context, Command, Flag, etc...)
  *
  * Copyright 2017 Google Inc.
  * Author: Joe Richey (joerichey@google.com)
@@ -17,34 +17,93 @@
  * the License.
  */
 
-// Package cmd is the common library for writing command line binaries.
-// This package is mainly a wrapper around github.com/urfave/cli, but provides
-// additional support to make the usage look similar to the man page.
-//
-// The main componets are the `Cmd`, `Argument`, and `Flag` types which can be
-// used to define a top-level command with many potential subcommands. This
-// package also presents a smaller interface than urfave/cli, making it easier
-// to use for other commands.
+// Package cmd is the common library for writing command line binaries. The main
+// componets are the `Command`, `Context`, `Argument`, and `Flag` types which
+// can be used to define a top-level command with many potential subcommands.
 package cmd
 
 import (
 	"fmt"
-	"io"
 	"os"
-	"text/template"
-	"time"
+	"path/filepath"
 
-	"github.com/blang/semver"
+	"github.com/pkg/errors"
 )
 
+// Command represents a command with many potential sub-commands.
+type Command struct {
+	Name             string
+	Title            string
+	UsageLines       []string
+	SubCommands      []*Command
+	InheritArguments bool
+	Arguments        []*Argument
+	InheritFlags     bool
+	Flags            []Flag
+	ManPage          *ManPage
+	Action           Action
+}
+
+// Run executes the command with os.Args, equivalent to c.RunArgs(os.Args).
+func (c *Command) Run() {
+	c.RunArgs(os.Args)
+}
+
+// RunArgs executes the command with the provided args. If the Name argument is
+// empty, args[0]'s basename is used instead. If the command fails, this method
+// will not return.
+func (c *Command) RunArgs(args []string) {
+	binaryPath, args := args[0], args[1:]
+	if c.Name == "" {
+		c.Name = filepath.Base(binaryPath)
+	}
+
+	// Create our initial context by sorting the arguments.
+	ctx := &Context{Command: c}
+	ctx.Args, ctx.flagArgs = sortArgs(args)
+
+	ctx.run()
+}
+
+// Action contains the implementation of a command. If a normal error is
+// returned, the error will be printed out (with an optional explanation) and
+// Run will exit with FailureCode. If a usage error is returned, the error and
+// the commnd's usage are printed out and Run will exit with UsageFailureCode.
+// Returning nil causes Run to return.
+type Action func(ctx *Context) error
+
 // Context represents the state of a running application, and is the only thing
-// passed to a CommandFunc.
+// passed to an Action.
 type Context struct {
-	Command  *Command
-	Parent   *Context
-	Info     *Info
-	Args     []string
+	// The current command being executed
+	Command *Command
+	// The context of the parent command before this command was executed.
+	// Nil if this is the root context.
+	Parent *Context
+	// The non-flag arguments being passed to the command.
+	Args []string
+	// The flag arguments being passed to the command.
 	flagArgs []string
+	// The mapping of error causes to help strings
+	errorMap map[error]string
+}
+
+// FullArguments returns the list of arguments for the current command and its
+// parent arguments (if InheritArguments) is true.
+func (ctx *Context) FullArguments() []*Argument {
+	if ctx.Parent == nil || !ctx.Command.InheritArguments {
+		return ctx.Command.Arguments
+	}
+	return append(ctx.Command.Arguments, ctx.Parent.FullArguments()...)
+}
+
+// FullFlags returns the list of flags for the current command and its parent
+// arguments (if InheritFlags) is true.
+func (ctx *Context) FullFlags() []Flag {
+	if ctx.Parent == nil || !ctx.Command.InheritFlags {
+		return ctx.Command.Flags
+	}
+	return append(ctx.Command.Flags, ctx.Parent.FullFlags()...)
 }
 
 // FullName returns the space-separated name of the command and all parents.
@@ -55,41 +114,30 @@ func (ctx *Context) FullName() string {
 	return fmt.Sprintf("%s %s", ctx.Parent.FullName(), ctx.Command.Name)
 }
 
+// Info returns the same information as cmd.Info. This method only exists so
+// that Info can be accessed in an output template.
+func (*Context) Info() *InfoData {
+	return Info
+}
+
 // ManPage returns the man page entry for this context. It is either the ManPage
 // for the the current command or the closet Parent.
 func (ctx *Context) ManPage() *ManPage {
-	if ctx.Command.ManPage.Section != 0 || ctx.Parent == nil {
+	if ctx.Parent == nil || ctx.Command.ManPage != nil {
 		return ctx.Command.ManPage
 	}
 	return ctx.Parent.ManPage()
 }
 
-// Creates an anonymous template from the text, and runs it with the provided
-// Context and writer. Panics if text has a bad format or execution fails.
-func (ctx *Context) executeTemplate(w io.Writer, text string) {
-	tmpl := template.Must(template.New("").Parse(text))
-	if err := tmpl.Execute(w, ctx); err != nil {
-		panic(err)
+// getHelp tries to find a helpMap and then lookup the error by it's cause.
+func (ctx *Context) getHelp(err error) string {
+	if ctx.errorMap != nil {
+		return ctx.errorMap[errors.Cause(err)]
 	}
-}
-
-func (ctx *Context) execute() {
-	fmt.Printf("%+v\n", ctx)
-	return
-}
-
-// Info is a parsed view of the corresponding global variables.
-type Info struct {
-	Version   semver.Version
-	BuildTime time.Time
-	Authors   []Author
-	Copyright string
-}
-
-// Author contains the contact information for a contributor.
-type Author struct {
-	Name  string
-	Email string
+	if ctx.Parent == nil {
+		return ""
+	}
+	return ctx.Parent.getHelp(err)
 }
 
 // Argument represents a parameter passed to a function. It has an optional
@@ -101,77 +149,10 @@ type Argument struct {
 
 func (a *Argument) String() string { return fmt.Sprintf("<%s>", a.ArgName) }
 
-// ManPage a man page with a title and section.
+// ManPage a man page with a name and section.
 type ManPage struct {
-	Title   string
+	Name    string
 	Section int
 }
 
-// CommandFunc contains the implementation of a command. If a normal error is
-// returned, the error will be printed out (with an optional explanation) and
-// Run will exit with FailureCode. If a usage error is returned, the error and
-// the commnd's usage are printed out and Run will exit with UsageFailureCode.
-// Returning nil causes Run to return.
-type CommandFunc func(ctx *Context) error
-
-// Command represents a command with many potential top-level commands. This is
-// transformed into a cli.Command in Run().
-type Command struct {
-	Name             string
-	Title            string
-	UsageLines       []string
-	SubCommands      []*Command
-	InheritArguments bool
-	Arguments        []*Argument
-	InheritFlags     bool
-	Flags            []Flag
-	ManPage          *ManPage
-	Action           CommandFunc
-}
-
-// Run executes the command with os.Args, equivalent to c.RunArgs(os.Args).
-func (c *Command) Run() {
-	c.RunArgs(os.Args)
-}
-
-// RunArgs executes the command with the provided args. If the Name argument is
-// empty, args[0]'s basename is used instead. If the command fails, this method
-// will not return.
-func (c *Command) RunArgs(args []string) {
-	binaryName, args := args[0], args[1:]
-	if c.Name == "" {
-		c.Name = binaryName
-	}
-
-	// Create our initial context by sorting the args and parsing the tags.
-	ctx := &Context{
-		Command: c,
-		Info:    parseInfo(),
-	}
-	ctx.Args, ctx.flagArgs = sortArgs(args)
-
-	ctx.execute()
-}
-
-// Divide the arguments into flag arguments (those starting with "-") and normal
-// arguments. If "--" appears in the list, it will classified as a normal
-// argument as well as all arguments following it. Also removes empty args.
-func sortArgs(args []string) (normalArgs, flagArgs []string) {
-	var arg string
-	for len(args) > 0 {
-		arg, args = args[0], args[1:]
-		if arg == "" {
-			continue
-		}
-		if arg == "--" {
-			normalArgs = append(normalArgs, arg)
-			normalArgs = append(normalArgs, args...)
-			return
-		} else if arg[0] == '-' {
-			flagArgs = append(flagArgs, arg)
-		} else {
-			normalArgs = append(normalArgs, arg)
-		}
-	}
-	return
-}
+func (m *ManPage) String() string { return fmt.Sprintf("%s(%d)", m.Name, m.Section) }
diff --git a/cmd/errors.go b/cmd/errors.go
index 07a1d05..0252fed 100644
--- a/cmd/errors.go
+++ b/cmd/errors.go
@@ -20,19 +20,59 @@
 package cmd
 
 import (
+	"fmt"
+	"os"
+
 	"github.com/pkg/errors"
 
 	"github.com/google/fscrypt/util"
 )
 
-// Common errors used across commands
+// Common errors used across tools
 var (
-	ErrUnknownVersion = errors.New("unknown (missing version tag)")
+	ErrUnknownVersion = errors.New("unknown version (missing version tag)")
 	ErrCanceled       = errors.New("operation canceled by user")
 	ErrMustForce      = errors.New("operation must be forced")
 	ErrNotRoot        = errors.New("operation must be run as root")
 )
 
+// Error return codes
+var (
+	FailureCode      = 1
+	UsageFailureCode = 2
+)
+
+// UsageError is an error type used to denote that a command was incorrectly
+// specified. Returning this type from an Action will cause print the command's
+// usage to os.Stdout before exiting with UsageFailureCode.
+type UsageError string
+
+func (u UsageError) Error() string { return string(u) }
+
+// CheckExpectedArgs returns a UsageError if the number of arguements in the
+// context does not match expectedArgs. If atMost is set, the number of args
+// is allowed to be less than expectedArgs.
+func CheckExpectedArgs(ctx *Context, expectedArgs int, atMost bool) error {
+	// Check the number of arguements and build the message.
+	nArgs := len(ctx.Args)
+	message := "expected"
+	if atMost {
+		if nArgs <= expectedArgs {
+			return nil
+		}
+		message += " at most"
+	} else {
+		if nArgs == expectedArgs {
+			return nil
+		}
+	}
+	// We have the wrong number of arguments
+	message += fmt.Sprintf(" %s, got %s",
+		Pluralize(expectedArgs, "argument"),
+		Pluralize(nArgs, "argument"))
+	return UsageError(message)
+}
+
 // CheckIfRoot returns an error if the current user is not the root user.
 func CheckIfRoot() error {
 	if id := util.CurrentUserID(); id != 0 {
@@ -40,3 +80,37 @@ func CheckIfRoot() error {
 	}
 	return nil
 }
+
+// CheckRequiredFlags returns a UsageError if all of the required flags are not
+// set. Only StringFlags are currently supported.
+func CheckRequiredFlags(flags []*StringFlag) error {
+	for _, flag := range flags {
+		if flag.Value == "" {
+			return UsageError(fmt.Sprintf("required flag %s not set", flag))
+		}
+	}
+	return nil
+}
+
+// processError TODO(joerichey)
+func (ctx *Context) processError(err error) {
+	if err == nil {
+		return
+	}
+
+	fmt.Fprintf(os.Stderr, "%s: %s\n", ctx.FullName(), err)
+	// Usage Errors should print the usage information
+	if _, ok := err.(UsageError); ok {
+		ExecuteTemplate(os.Stderr, TemplateUsage, ctx)
+		os.Exit(UsageFailureCode)
+		return
+	}
+
+	// Errors with a help text should print it out.
+	if helpText := ctx.getHelp(err); helpText != "" {
+		fmt.Fprintln(os.Stderr)
+		fmt.Fprintln(os.Stderr, wrapText(helpText, 0))
+	}
+	os.Exit(FailureCode)
+	return
+}
diff --git a/cmd/flag.go b/cmd/flag.go
index 5f864b9..24fd86d 100644
--- a/cmd/flag.go
+++ b/cmd/flag.go
@@ -26,6 +26,29 @@ import (
 	"time"

 )

 

+// Useful flags that can be used with a variety of commands.

+var (

+	HelpFlag = &BoolFlag{

+		Name:      "help",

+		ShortName: 'h',

+		Usage:     "Prints a help text for any command or sub-command.",

+	}

+	VerboseFlag = &BoolFlag{

+		Name:  "verbose",

+		Usage: "Prints additional debug messages.",

+	}

+	QuietFlag = &BoolFlag{

+		Name: "quiet",

+		Usage: `Prints nothing except for errors and uses any default

+		option instead of prompting the user.`,

+	}

+	ForceFlag = &BoolFlag{

+		Name: "force",

+		Usage: `Print no confirmation prompts or warnings and

+		automatically proceed with the requested action.`,

+	}

+)

+

 // Flag represents a flag that can be passed to a command. The Name, ArgName,

 // and Usage are used to format and display the flag.

 type Flag interface {

@@ -38,7 +61,7 @@ type Flag interface {
 }

 

 // Formats as "--name" or as "--name=<argName>" if argName is present.

-func formatHelper(name, argName string) string {

+func flagFormatHelper(name, argName string) string {

 	if argName != "" {

 		return fmt.Sprintf("--%s=<%s>", name, argName)

 	}

@@ -46,7 +69,7 @@ func formatHelper(name, argName string) string {
 }

 

 // Appends (default: <default>) to the usage if defaultString is present.

-func usageHelper(usage, defaultString string) string {

+func flagUsageHelper(usage, defaultString string) string {

 	if defaultString != "" {

 		usage += fmt.Sprintf(" (default: %s)", defaultString)

 	}

@@ -55,25 +78,37 @@ func usageHelper(usage, defaultString string) string {
 

 // BoolFlag is a Flag of type bool.

 type BoolFlag struct {

-	Name    string

-	Usage   string

-	Default bool

-	Value   bool

+	Name      string

+	ShortName byte

+	Usage     string

+	Default   bool

+	Value     bool

 }

 

 // String always uses the smaller format, as it has no ArgName.

-func (f *BoolFlag) String() string { return formatHelper(f.Name, "") }

+func (f *BoolFlag) String() string {

+	name := f.Name

+	if f.ShortName != 0 {

+		name += ", -" + string(f.ShortName)

+	}

+	return flagFormatHelper(name, "")

+}

 

 // FullUsage shows the default if it's true (flag is implicitly passed).

 func (f *BoolFlag) FullUsage() string {

 	if !f.Default {

-		return usageHelper(f.Usage, "")

+		return flagUsageHelper(f.Usage, "")

 	}

-	return usageHelper(f.Usage, "true")

+	return flagUsageHelper(f.Usage, "true")

 }

 

 // Apply uses BoolFlag's value to set a flag.BoolVar on the FlagSet.

-func (f *BoolFlag) Apply(s *flag.FlagSet) { s.BoolVar(&f.Value, f.Name, f.Default, f.Usage) }

+func (f *BoolFlag) Apply(s *flag.FlagSet) {

+	s.BoolVar(&f.Value, f.Name, f.Default, f.Usage)

+	if f.ShortName != 0 {

+		s.BoolVar(&f.Value, string(f.ShortName), f.Default, f.Usage)

+	}

+}

 

 // StringFlag is a Flag of type string.

 type StringFlag struct {

@@ -84,14 +119,14 @@ type StringFlag struct {
 	Value   string

 }

 

-func (f *StringFlag) String() string { return formatHelper(f.Name, f.ArgName) }

+func (f *StringFlag) String() string { return flagFormatHelper(f.Name, f.ArgName) }

 

 // FullUsage shows the deafult if the string is non-empty.

 func (f *StringFlag) FullUsage() string {

 	if f.Default == "" {

-		return usageHelper(f.Usage, "")

+		return flagUsageHelper(f.Usage, "")

 	}

-	return usageHelper(f.Usage, strconv.Quote(f.Default))

+	return flagUsageHelper(f.Usage, strconv.Quote(f.Default))

 }

 

 // Apply uses StringFlag's value to set a flag.StringVar on the FlagSet.

@@ -106,14 +141,14 @@ type DurationFlag struct {
 	Value   time.Duration

 }

 

-func (f *DurationFlag) String() string { return formatHelper(f.Name, f.ArgName) }

+func (f *DurationFlag) String() string { return flagFormatHelper(f.Name, f.ArgName) }

 

 // FullUsage shows the default if the duration is non-zero.

 func (f *DurationFlag) FullUsage() string {

 	if f.Default == 0 {

-		return usageHelper(f.Usage, "")

+		return flagUsageHelper(f.Usage, "")

 	}

-	return usageHelper(f.Usage, f.Default.String())

+	return flagUsageHelper(f.Usage, f.Default.String())

 }

 

 // Apply uses DurationFlag's value to set a flag.DurationVar on the FlagSet.

diff --git a/cmd/output.go b/cmd/format.go
index c3a79a4..69fd0e9 100644
--- a/cmd/output.go
+++ b/cmd/format.go
@@ -1,5 +1,5 @@
 /*
- * output.go - Functions for handling command line formatting and output.
+ * format.go - Functions for handling output formatting.
  *
  * Copyright 2017 Google Inc.
  * Author: Joe Richey (joerichey@google.com)
@@ -23,16 +23,22 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
-	"log"
 	"os"
 	"strings"
+	"text/template"
 	"unicode/utf8"
 
 	"github.com/google/fscrypt/util"
 	"golang.org/x/crypto/ssh/terminal"
 )
 
+// Suffixes for questions with a yes or no default
+const (
+	defaultYesSuffix = "[Y/n]"
+	defaultNoSuffix  = "[y/N]"
+)
+
+// Variables which control how output is formmatted and where it goes.
 var (
 	// TabWidth is the number of spaces used to display a tab.
 	TabWidth = 8
@@ -48,34 +54,6 @@ var (
 	// output (errors should just return the appropriate error). If not set,
 	// it is automatically set based on the provided flags.
 	Output io.Writer
-	// HelpFlag writes help to Stdout
-	HelpFlag = &BoolFlag{
-		Name:  "help",
-		Usage: "Prints this help text for commands and subcommands",
-	}
-	// VerboseFlag indicates that all logging output should be printed.
-	VerboseFlag = &BoolFlag{
-		Name:  "verbose",
-		Usage: "Prints additional debug messages.",
-	}
-	// QuietFlag indicates that no normal output should be printed.
-	QuietFlag = &BoolFlag{
-		Name: "quiet",
-		Usage: `Prints nothing except for errors and uses any default
-		option instead of prompting the user.`,
-	}
-	// ForceFlag indicates that the operation should proceed if possible.
-	ForceFlag = &BoolFlag{
-		Name: "force",
-		Usage: `Print no confirmation prompts or warnings and
-		automatically proceed with the requested action.`,
-	}
-)
-
-// Suffixes for questions with a yes or no default
-const (
-	defaultYesSuffix = "[Y/n]"
-	defaultNoSuffix  = "[y/N]"
 )
 
 // We use the width of the terminal unless we cannot get the width.
@@ -92,18 +70,21 @@ func init() {
 }
 
 // Takes an input string text, and wraps the text so that each line begins with
-// numTabs tabs and ends with a newline (except the last line), and each line
-// has length less than lineLength. If the text contains a word which is too
-// long, that word gets its own line.
+// numTabs tabs (except the first line) and ends with a newline (except the last
+// line), and each line has length less than lineLength. If the text contains a
+// word which is too long, that word gets its own line.
 func wrapText(text string, numTabs int) string {
 	// We use a buffer to format the wrapped text so we get O(n) runtime
 	var buffer bytes.Buffer
 	spaceLeft := 0
 	maxTextLen := LineLength - numTabs*TabWidth
 	delimiter := strings.Repeat("\t", numTabs)
-	for _, word := range strings.Fields(text) {
+	for i, word := range strings.Fields(text) {
 		wordLen := utf8.RuneCountInString(word)
-		if wordLen >= spaceLeft {
+		if i == 0 {
+			buffer.WriteString(word)
+			spaceLeft = maxTextLen - wordLen
+		} else if wordLen >= spaceLeft {
 			// If no room left, write the word on the next line.
 			buffer.WriteString("\n")
 			buffer.WriteString(delimiter)
@@ -120,22 +101,22 @@ func wrapText(text string, numTabs int) string {
 	return buffer.String()
 }
 
-// Configures the Output and log output io.Writers. Called before running
-// commands but after processing flags.
-func setupOutput() {
-	if VerboseFlag.Value {
-		log.SetOutput(os.Stdout)
-	} else {
-		log.SetOutput(ioutil.Discard)
-	}
-	if Output != nil {
-		return
+// Add words to this map if pluralization does not just involve adding an s.
+var plurals = map[string]string{
+	"policy": "policies",
+}
+
+// Pluralize returns the correct pluralization of a work along with the
+// specified count. This means Pluralize(1, "policy") = "1 policy" but
+// Pluralize(2, "policy") = "2 policies".
+func Pluralize(count int, word string) string {
+	if count == 1 {
+		return fmt.Sprintf("%d %s", count, word)
 	}
-	if QuietFlag.Value {
-		Output = ioutil.Discard
-	} else {
-		Output = os.Stdout
+	if plural, ok := plurals[word]; ok {
+		return fmt.Sprintf("%d %s", count, plural)
 	}
+	return fmt.Sprintf("%d %ss", count, word)
 }
 
 // AskQuestion asks the user a yes or no question. Returning a boolean on a
@@ -199,3 +180,14 @@ func AskConfirmation(question, warning string, defaultChoice bool) error {
 	}
 	return nil
 }
+
+// ExecuteTemplate creates an anonymous template from the text, and runs it with
+// the provided Context and writer. Panics if text cannot be executed.
+func ExecuteTemplate(w io.Writer, text string, ctx *Context) {
+	tmpl := template.Must(template.New("").Funcs(template.FuncMap{
+		"wrapText": wrapText,
+	}).Parse(text))
+	if err := tmpl.Execute(w, ctx); err != nil {
+		panic(err)
+	}
+}
diff --git a/cmd/fscrypt/commands.go b/cmd/fscrypt/commands.go
index 2f23a0f..e8d32da 100644
--- a/cmd/fscrypt/commands.go
+++ b/cmd/fscrypt/commands.go
@@ -35,7 +35,6 @@ import (
 	"github.com/google/fscrypt/util"
 )
 
-// Setup is a command which can to global or per-filesystem initialization.
 var Setup = cli.Command{
 	Name:      "setup",
 	ArgsUsage: fmt.Sprintf("[%s]", mountpointArg),
diff --git a/cmd/fscrypt/errors.go b/cmd/fscrypt/errors.go
index 81a6798..4ce6133 100644
--- a/cmd/fscrypt/errors.go
+++ b/cmd/fscrypt/errors.go
@@ -22,10 +22,7 @@
 package main
 
 import (
-	"bytes"
 	"fmt"
-	"os"
-	"path/filepath"
 	"unicode/utf8"
 
 	"github.com/pkg/errors"
@@ -165,40 +162,6 @@ func newExitError(c *cli.Context, err error) error {
 	return cli.NewExitError(message, failureExitCode)
 }
 
-// usageError implements cli.ExitCoder to will print the usage and the return a
-// non-zero value. This error should be used when a command is used incorrectly.
-type usageError struct {
-	c       *cli.Context
-	message string
-}
-
-func (u *usageError) Error() string {
-	return fmt.Sprintf("%s: %s", getFullName(u.c), u.message)
-}
-
-// We get the help to print after the error by having it run right before the
-// application exits. This is very nasty, but there isn't a better way to do it
-// with the constraints of urfave/cli.
-func (u *usageError) ExitCode() int {
-	// Redirect help output to a buffer, so we can customize it.
-	buf := new(bytes.Buffer)
-	oldWriter := u.c.App.Writer
-	u.c.App.Writer = buf
-
-	// Get the appropriate help
-	if getFullName(u.c) == filepath.Base(os.Args[0]) {
-		cli.ShowAppHelp(u.c)
-	} else {
-		cli.ShowCommandHelp(u.c, u.c.Command.Name)
-	}
-
-	// Remove first line from help and print it out
-	buf.ReadBytes('\n')
-	buf.WriteTo(oldWriter)
-	u.c.App.Writer = oldWriter
-	return failureExitCode
-}
-
 // expectedArgsErr creates a usage error for the incorrect number of arguments
 // being specified. atMost should be true only if any number of arguments from 0
 // to expectedArgs would be acceptable.
diff --git a/cmd/fscrypt/flags.go b/cmd/fscrypt/flags.go
index 5137eff..69126bc 100644
--- a/cmd/fscrypt/flags.go
+++ b/cmd/fscrypt/flags.go
@@ -22,133 +22,19 @@
 package main
 
 import (
-	"flag"
 	"fmt"
 	"log"
 	"os/user"
 	"regexp"
-	"strconv"
 	"time"
 
-	"github.com/urfave/cli"
-
 	"github.com/google/fscrypt/actions"
 	"github.com/google/fscrypt/security"
 	"github.com/google/fscrypt/util"
 )
 
-// We define the types boolFlag, durationFlag, and stringFlag here instead of
-// using those present in urfave/cli because we need them to conform to the
-// prettyFlag interface (in format.go). The Getters just get the corresponding
-// variables, String() just uses longDisplay, and Apply just sets the
-// corresponding type of flag.
-type boolFlag struct {
-	Name    string
-	Usage   string
-	Default bool
-	Value   bool
-}
-
-func (b *boolFlag) GetName() string    { return b.Name }
-func (b *boolFlag) GetArgName() string { return "" }
-func (b *boolFlag) GetUsage() string   { return b.Usage }
-
-func (b *boolFlag) String() string {
-	if !b.Default {
-		return longDisplay(b)
-	}
-	return longDisplay(b, strconv.FormatBool(b.Default))
-}
-
-func (b *boolFlag) Apply(set *flag.FlagSet) {
-	set.BoolVar(&b.Value, b.Name, b.Default, b.Usage)
-}
-
-type durationFlag struct {
-	Name    string
-	ArgName string
-	Usage   string
-	Default time.Duration
-	Value   time.Duration
-}
-
-func (d *durationFlag) GetName() string    { return d.Name }
-func (d *durationFlag) GetArgName() string { return d.ArgName }
-func (d *durationFlag) GetUsage() string   { return d.Usage }
-
-func (d *durationFlag) String() string {
-	if d.Default == 0 {
-		return longDisplay(d)
-	}
-	return longDisplay(d, d.Value.String())
-}
-
-func (d *durationFlag) Apply(set *flag.FlagSet) {
-	set.DurationVar(&d.Value, d.Name, d.Default, d.Usage)
-}
-
-type stringFlag struct {
-	Name    string
-	ArgName string
-	Usage   string
-	Default string
-	Value   string
-}
-
-func (s *stringFlag) GetName() string    { return s.Name }
-func (s *stringFlag) GetArgName() string { return s.ArgName }
-func (s *stringFlag) GetUsage() string   { return s.Usage }
-
-func (s *stringFlag) String() string {
-	if s.Default == "" {
-		return longDisplay(s)
-	}
-	return longDisplay(s, strconv.Quote(s.Default))
-}
-
-func (s *stringFlag) Apply(set *flag.FlagSet) {
-	set.StringVar(&s.Value, s.Name, s.Default, s.Usage)
-}
-
-var (
-	// allFlags contains every defined flag (used for formatting).
-	// UPDATE THIS ARRAY WHEN ADDING NEW FLAGS!!!
-	// TODO(joerichey) add presubmit rule to enforce this
-	allFlags = []prettyFlag{helpFlag, versionFlag, verboseFlag, quietFlag,
-		forceFlag, legacyFlag, skipUnlockFlag, timeTargetFlag,
-		sourceFlag, nameFlag, keyFileFlag, protectorFlag,
-		unlockWithFlag, policyFlag}
-	// universalFlags contains flags that should be on every command
-	universalFlags = []cli.Flag{verboseFlag, quietFlag, helpFlag}
-)
-
 // Bool flags: used to switch some behavior on or off
 var (
-	helpFlag = &boolFlag{
-		Name:  "help",
-		Usage: `Prints help screen for commands and subcommands.`,
-	}
-	versionFlag = &boolFlag{
-		Name:  "version",
-		Usage: `Prints version and license information.`,
-	}
-	verboseFlag = &boolFlag{
-		Name:  "verbose",
-		Usage: `Prints additional debug messages to standard output.`,
-	}
-	quietFlag = &boolFlag{
-		Name: "quiet",
-		Usage: `Prints nothing to standard output except for errors.
-			Selects the default for any options that would normally
-			show a prompt.`,
-	}
-	forceFlag = &boolFlag{
-		Name: "force",
-		Usage: fmt.Sprintf(`Suppresses all confirmation prompts and
-			warnings, causing any action to automatically proceed.
-			WARNING: This bypasses confirmations for protective
-			operations, use with care.`),
-	}
 	legacyFlag = &boolFlag{
 		Name: "legacy",
 		Usage: `Allow for support of older kernels with ext4 (before
diff --git a/cmd/fscrypt/format.go b/cmd/fscrypt/format.go
deleted file mode 100644
index ef009d3..0000000
--- a/cmd/fscrypt/format.go
+++ /dev/null
@@ -1,162 +0,0 @@
-/*
- * format.go - Contains all the functionality for formatting the command line
- * output. This includes formatting the description and flags so that the whole
- * text is <= LineLength characters.
- *
- * Copyright 2017 Google Inc.
- * Author: Joe Richey (joerichey@google.com)
- *
- * 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 main
-
-import (
-	"bytes"
-	"fmt"
-	"os"
-	"regexp"
-	"strings"
-	"unicode/utf8"
-
-	"github.com/urfave/cli"
-	"golang.org/x/crypto/ssh/terminal"
-
-	"github.com/google/fscrypt/util"
-)
-
-var (
-	// lineLength is the maximum width of fscrypt's formatted output. It is
-	// usually the width of the terminal.
-	lineLength         int
-	fallbackLineLength = 80 // fallback is punch cards
-	maxLineLength      = 120
-	// IndentLength is the number spaces to indent by.
-	indentLength = 2
-	// length of the longest shortDisplay for a flag
-	maxShortDisplay int
-	// how much the a flag's usage text needs to be moved over
-	flagPaddingLength int
-)
-
-// We use the init() function to compute our longest short display length. This
-// is then used to compute the formatting and padding strings. This ensures we
-// will always have room to display our flags, and the flag descriptions always
-// appear in the same place.
-func init() {
-	for _, flag := range allFlags {
-		displayLength := utf8.RuneCountInString(shortDisplay(flag))
-		if displayLength > maxShortDisplay {
-			maxShortDisplay = displayLength
-		}
-	}
-
-	// Pad usage enough so the flags have room.
-	flagPaddingLength = maxShortDisplay + 2*indentLength
-
-	// We use the width of the terminal unless we cannot get the width.
-	width, _, err := terminal.GetSize(int(os.Stdout.Fd()))
-	if err != nil {
-		lineLength = fallbackLineLength
-	} else {
-		lineLength = util.MinInt(width, maxLineLength)
-	}
-
-}
-
-// Flags that conform to this interface can be used with an urfave/cli
-// application and can be printed in the correct format.
-type prettyFlag interface {
-	cli.Flag
-	GetArgName() string
-	GetUsage() string
-}
-
-// How a flag should appear on the command line. We have two formats:
-//  --name
-//  --name=ARG_NAME
-// The ARG_NAME appears if the prettyFlag's GetArgName() method returns a
-// non-empty string. The returned string from shortDisplay() does not include
-// any leading or trailing whitespace.
-func shortDisplay(f prettyFlag) string {
-	if argName := f.GetArgName(); argName != "" {
-		return fmt.Sprintf("--%s=%s", f.GetName(), argName)
-	}
-	return fmt.Sprintf("--%s", f.GetName())
-}
-
-// How our flags should appear when displaying their usage. An example would be:
-//
-//  --help                     Prints help screen for commands and subcommands.
-//
-// If a default is specified, this if appended to the usage. Example:
-//
-//  --legacy                   Allow for support of older kernels with ext4
-//                             (before v4.8) and F2FS (before v4.6) filesystems.
-//                             (default: true)
-//
-func longDisplay(f prettyFlag, defaultString ...string) string {
-	usage := f.GetUsage()
-	if len(defaultString) > 0 {
-		usage += fmt.Sprintf(" (default: %v)", defaultString[0])
-	}
-
-	// We pad the the shortDisplay on the right with enough spaces to equal
-	// the longest flag's display
-	shortDisp := shortDisplay(f)
-	length := utf8.RuneCountInString(shortDisp)
-	shortDisp += strings.Repeat(" ", maxShortDisplay-length)
-
-	return indent + shortDisp + indent + wrapText(usage, flagPaddingLength)
-}
-
-// Regex that determines if we are starting an ordered list
-var listRegex = regexp.MustCompile(`^\([\d]+\)$`)
-
-// Takes an input string text, and wraps the text so that each line begins with
-// padding spaces (except for the first line), ends with a newline (except the
-// last line), and each line has length less than lineLength. If the text
-// contains a word which is too long, that word gets its own line.
-func wrapText(text string, padding int) string {
-	// We use a buffer to format the wrapped text so we get O(n) runtime
-	var buffer bytes.Buffer
-	spaceLeft := 0
-	maxTextLen := lineLength - padding
-	delimiter := strings.Repeat(" ", padding)
-	for i, word := range strings.Fields(text) {
-		wordLen := utf8.RuneCountInString(word)
-		switch {
-		case i == 0:
-			// No delimiter for the first line
-			buffer.WriteString(word)
-			spaceLeft = maxTextLen - wordLen
-		case listRegex.Match([]byte(word)):
-			// Add an additional line to separate list items.
-			buffer.WriteString("\n")
-			fallthrough
-		case wordLen+1 > spaceLeft:
-			// If no room left, write the word on the next line.
-			buffer.WriteString("\n")
-			buffer.WriteString(delimiter)
-			buffer.WriteString(word)
-			spaceLeft = maxTextLen - wordLen
-		default:
-			// Write word on this line
-			buffer.WriteByte(' ')
-			buffer.WriteString(word)
-			spaceLeft -= 1 + wordLen
-		}
-	}
-
-	return buffer.String()
-}
diff --git a/cmd/fscrypt/fscrypt.go b/cmd/fscrypt/fscrypt.go
index d6162f6..f1649fc 100644
--- a/cmd/fscrypt/fscrypt.go
+++ b/cmd/fscrypt/fscrypt.go
@@ -22,127 +22,63 @@
 fscrypt is a command line tool for managing linux filesystem encryption.
 */
 
-// +build linux,cgo
-
 package main
 
 import (
 	"fmt"
-	"io/ioutil"
-	"log"
-	"os"
-	"time"
-
-	"github.com/urfave/cli"
-)
 
-var (
-	// Current version of the program (set by Makefile)
-	version string
-	// Formatted build time (set by Makefile)
-	buildTime string
-	// Authors to display in the info command
-	Authors = []cli.Author{{
-		Name:  "Joe Richey",
-		Email: "joerichey@google.com",
-	}}
+	"github.com/google/fscrypt/cmd"
 )
 
-func main() {
-	cli.AppHelpTemplate = appHelpTemplate
-	cli.CommandHelpTemplate = commandHelpTemplate
-	cli.SubcommandHelpTemplate = subcommandHelpTemplate
-
-	// Create our command line application
-	app := cli.NewApp()
-	app.Usage = shortUsage
-	app.Authors = Authors
-	app.Copyright = apache2GoogleCopyright
-
-	// Grab the version and compilation time passed in from the Makefile.
-	app.Version = version
-	app.Compiled, _ = time.Parse(time.UnixDate, buildTime)
-	app.OnUsageError = onUsageError
-
-	// Setup global flags
-	cli.HelpFlag = helpFlag
-	cli.VersionFlag = versionFlag
-	cli.VersionPrinter = func(c *cli.Context) {
-		cli.HelpPrinter(c.App.Writer, versionInfoTemplate, c.App)
-	}
-	app.Flags = universalFlags
-
-	// We hide the help subcommand so that "fscrypt <command> --help" works
-	// and "fscrypt <command> help" does not.
-	app.HideHelp = true
-
-	// Initialize command list and setup all of the commands.
-	app.Action = defaultAction
-	app.Commands = []cli.Command{Setup, Encrypt, Unlock, Purge, Status, Metadata}
-	for i := range app.Commands {
-		setupCommand(&app.Commands[i])
-	}
-
-	app.Run(os.Args)
+func main() { fscryptCommand.Run() }
+
+var fscryptCommand = cmd.Command{
+	Title: "manage linux filesystem encryption",
+	UsageLines: []string{
+		fmt.Sprintf("<command> [arguments] [command options] [%s | %s]",
+			cmd.VerboseFlag, cmd.QuietFlag),
+		cmd.VersionUsage,
+	},
+	SubCommands: []*Command{
+		&setupCommand,
+		&encryptCommand,
+		// unlockCommand,
+		// purgeCommand,
+		// statusCommand,
+		// metadataCommand,
+		cmd.VersionCommand,
+	},
+	Flags:   []cmd.Flag{cmd.VerboseFlag, cmd.QuietFlag, cmd.HelpFlag},
+	ManPage: &cmd.ManPage{Name: "fscrypt", Section: 8},
 }
 
-// setupCommand performs some common setup for each command. This includes
-// hiding the help, formating the description, adding in the necessary
-// flags, setting up error handlers, etc... Note that the command is modified
-// in place and its subcommands are also setup.
-func setupCommand(command *cli.Command) {
-	command.Description = wrapText(command.Description, indentLength)
-	command.HideHelp = true
-	command.Flags = append(command.Flags, universalFlags...)
-
-	if command.Action == nil {
-		command.Action = defaultAction
-	}
-
-	// Setup function handlers
-	command.OnUsageError = onUsageError
-	if len(command.Subcommands) == 0 {
-		command.Before = setupBefore
-	} else {
-		// Cleanup subcommands (if applicable)
-		for i := range command.Subcommands {
-			setupCommand(&command.Subcommands[i])
-		}
-	}
+// setup performs global or per-filesystem initialization of fscrypt data.
+var setupCommand = &cmd.Command{
+	Name:  "setup",
+	Title: "setup a system/filesystem to use fscrypt",
+	UsageLines: []string{
+		fmt.Sprintf("[options]"),
+		fmt.Sprintf("%s [%s]", mountpointArg, cmd.ForceFlag),
+	},
+	Arguments:    []*cmd.Argument{mountpointArg},
+	InheritFlags: true,
+	Flags:        []cmd.Flag{configFileFlag, targetFlag, legacyFlag, cmd.ForceFlag},
+	ManPage:      &cmd.ManPage{Name: "fscrypt-setup", Section: 8},
+	Action:       setupAction,
 }
 
-// setupBefore makes sure our logs, errors, and output are going to the correct
-// io.Writers and that we haven't over-specified our flags. We only print the
-// logs when using verbose, and only print normal stuff when not using quiet.
-// When running with sudo, this function also verifies that we have the proper
-// keyring linkage enabled.
-func setupBefore(c *cli.Context) error {
-	log.SetOutput(ioutil.Discard)
-	c.App.Writer = ioutil.Discard
-
-	if verboseFlag.Value {
-		log.SetOutput(os.Stdout)
+func setupAction(c *cmd.Context) error {
+	switch len(c.Args) {
+	case 0:
+		// Case (1) - global setup
+		return createGlobalConfig(configFileFlag.Value)
+	case 1:
+		// Case (2) - filesystem setup
+		return setupFilesystem(c.Args[0])
+	default:
+		return cmd.CheckExpectedArgs(c, 1, true)
 	}
-	if !quietFlag.Value {
-		c.App.Writer = os.Stdout
-	}
-	return nil
 }
 
-// defaultAction will be run when no command is specified.
-func defaultAction(c *cli.Context) error {
-	// Always default to showing the help
-	if helpFlag.Value {
-		cli.ShowAppHelp(c)
-		return nil
-	}
-
-	// Only exit when not calling with the help command
-	var message string
-	if args := c.Args(); args.Present() {
-		message = fmt.Sprintf("command \"%s\" not found", args.First())
-	} else {
-		message = "no command was specified"
-	}
-	return &usageError{c, message}
-}
+// encrypt performs the functions of setupDirectory and Unlock in one command.
+var encryptCommand = &cmd.Command{}
diff --git a/cmd/fscrypt/prompt.go b/cmd/fscrypt/prompt.go
index 0031e8f..bccf534 100644
--- a/cmd/fscrypt/prompt.go
+++ b/cmd/fscrypt/prompt.go
@@ -25,7 +25,6 @@ import (
 	"os"
 	"os/user"
 	"strconv"
-	"strings"
 
 	"github.com/pkg/errors"
 
@@ -47,67 +46,6 @@ var sourceDescriptions = map[metadata.SourceType]string{
 	metadata.SourceType_raw_key:           "A raw 256-bit key",
 }
 
-// askQuestion asks the user a yes or no question. Returning a boolean on a
-// successful answer and an error if there was not a response from the user.
-// Returns the defaultChoice on empty input (or in quiet mode).
-func askQuestion(question string, defaultChoice bool) (bool, error) {
-	// If in quiet mode, we just use the default
-	if quietFlag.Value {
-		return defaultChoice, nil
-	}
-	// Loop until failure or valid input
-	for {
-		if defaultChoice {
-			fmt.Print(question + defaultYesSuffix)
-		} else {
-			fmt.Print(question + defaultNoSuffix)
-		}
-
-		input, err := util.ReadLine()
-		if err != nil {
-			return false, err
-		}
-
-		switch strings.ToLower(input) {
-		case "y", "yes":
-			return true, nil
-		case "n", "no":
-			return false, nil
-		case "":
-			return defaultChoice, nil
-		}
-	}
-}
-
-// askConfirmation asks the user for confirmation of a specific action. An error
-// is returned if the user declines or IO fails.
-func askConfirmation(question string, defaultChoice bool, warning string) error {
-	// All confirmations are "yes" if we are forcing.
-	if forceFlag.Value {
-		return nil
-	}
-
-	// Defaults of "no" require forcing.
-	if !defaultChoice {
-		if quietFlag.Value {
-			return ErrNoDesctructiveOps
-		}
-	}
-
-	if warning != "" && !quietFlag.Value {
-		fmt.Println(wrapText("WARNING: "+warning, 0))
-	}
-
-	confirmed, err := askQuestion(question, defaultChoice)
-	if err != nil {
-		return err
-	}
-	if !confirmed {
-		return ErrCanceled
-	}
-	return nil
-}
-
 // usernameFromID returns the username for the provided UID. If the UID does not
 // correspond to a user or the username is blank, an error is returned.
 func usernameFromID(uid int64) (string, error) {
diff --git a/cmd/fscrypt/setup.go b/cmd/fscrypt/setup.go
index 72dfbdb..63f0c51 100644
--- a/cmd/fscrypt/setup.go
+++ b/cmd/fscrypt/setup.go
@@ -22,46 +22,45 @@ package main
 
 import (
 	"fmt"
-	"io"
 	"os"
 
 	"github.com/google/fscrypt/actions"
-	"github.com/google/fscrypt/util"
+	"github.com/google/fscrypt/cmd"
 )
 
 // createGlobalConfig creates (or overwrites) the global config file
-func createGlobalConfig(w io.Writer, path string) error {
-	if !util.IsUserRoot() {
-		return ErrMustBeRoot
+func createGlobalConfig(path string) error {
+	if err := cmd.CheckIfRoot(); err != nil {
+		return err
 	}
 
 	// Ask to create or replace the config file
 	_, err := os.Stat(path)
 	switch {
 	case err == nil:
-		err = askConfirmation(fmt.Sprintf("Replace %q?", path), false, "")
+		err = cmd.AskConfirmation(fmt.Sprintf("Replace %q?", path), "", false)
 		if err == nil {
 			err = os.Remove(path)
 		}
 	case os.IsNotExist(err):
-		err = askConfirmation(fmt.Sprintf("Create %q?", path), true, "")
+		err = cmd.AskConfirmation(fmt.Sprintf("Create %q?", path), "", true)
 	}
 	if err != nil {
 		return err
 	}
 
-	fmt.Fprintln(w, "Customizing passphrase hashing difficulty for this system...")
+	fmt.Fprintln(cmd.Output, "Customizing passphrase hashing difficulty for this system...")
 	err = actions.CreateConfigFile(timeTargetFlag.Value, legacyFlag.Value)
 	if err != nil {
 		return err
 	}
 
-	fmt.Fprintf(w, "Created global config file at %q.\n", path)
+	fmt.Fprintf(cmd.Output, "Created global config file at %q.\n", path)
 	return nil
 }
 
 // setupFilesystem creates the directories for a filesystem to use fscrypt.
-func setupFilesystem(w io.Writer, path string) error {
+func setupFilesystem(path string) error {
 	ctx, err := actions.NewContextFromMountpoint(path, nil)
 	if err != nil {
 		return err
@@ -71,8 +70,8 @@ func setupFilesystem(w io.Writer, path string) error {
 		return err
 	}
 
-	fmt.Fprintf(w, "Metadata directories created at %q.\n", ctx.Mount.BaseDir())
-	fmt.Fprintf(w, "Filesystem %q (%s) ready for use with %s encryption.\n",
+	fmt.Fprintf(Output, "Metadata directories created at %q.\n", ctx.Mount.BaseDir())
+	fmt.Fprintf(Output, "Filesystem %q (%s) ready for use with %s encryption.\n",
 		ctx.Mount.Path, ctx.Mount.Device, ctx.Mount.Filesystem)
 	return nil
 }
diff --git a/cmd/fscrypt/strings.go b/cmd/fscrypt/strings.go
index e90abe1..07b6b64 100644
--- a/cmd/fscrypt/strings.go
+++ b/cmd/fscrypt/strings.go
@@ -22,26 +22,6 @@ package main
 
 import (
 	"fmt"
-	"strings"
-)
-
-// Global application strings
-const (
-	shortUsage = "A tool for managing Linux filesystem encryption"
-
-	apache2GoogleCopyright = `Copyright 2017 Google, Inc.
-
-  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.`
 )
 
 // Argument usage strings
@@ -52,76 +32,6 @@ const (
 	mountpointIDArg = mountpointArg + ":ID"
 )
 
-// Text Templates which format our command line output (using text/template)
-var (
-	// indent is the prefix for the output lines in each section
-	indent = strings.Repeat(" ", indentLength)
-	// Top level help output: what is printed for "fscrypt" or "fscrypt --help"
-	appHelpTemplate = `{{.HelpName}} - {{.Usage}}
-
-Usage:
-` + indent + `{{.HelpName}} COMMAND [arguments] [options]
-
-Commands:{{range .VisibleCommands}}
-` + indent + `{{join .Names ", "}}{{"\t- "}}{{.Usage}}{{end}}
-{{if .Description}}
-Description:
-` + indent + `{{.Description}}
-{{end}}
-Options:
-{{range .VisibleFlags}}{{.}}
-
-{{end}}`
-
-	// Command help output, used when a command has no subcommands
-	commandHelpTemplate = `{{.HelpName}} - {{.Usage}}
-
-Usage:
-` + indent + `{{.HelpName}}{{if .ArgsUsage}} {{.ArgsUsage}}{{end}}{{if .VisibleFlags}} [options]{{end}}
-{{if .Description}}
-Description:
-` + indent + `{{.Description}}
-{{end}}{{if .VisibleFlags}}
-Options:
-{{range .VisibleFlags}}{{.}}
-
-{{end}}{{end}}`
-
-	// Subcommand help output, used when a command has subcommands
-	subcommandHelpTemplate = `{{.HelpName}} - {{.Usage}}
-
-Usage:
-` + indent + `{{.HelpName}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}SUBCOMMAND [arguments]{{end}}{{if .VisibleFlags}} [options]{{end}}
-
-Subcommands:{{range .VisibleCommands}}
-` + indent + `{{join .Names ", "}}{{"\t- "}}{{.Usage}}{{end}}
-{{if .Description}}
-Description:
-` + indent + `{{.Description}}
-{{end}}{{if .VisibleFlags}}
-Options:
-{{range .VisibleFlags}}{{.}}
-
-{{end}}{{end}}`
-
-	// Additional info, used with "fscrypt version"
-	versionInfoTemplate = `{{.HelpName}} - {{.Usage}}
-
-{{if .Version}}Version:
-` + indent + `{{.Version}}
-
-{{end}}{{if .Compiled}}Compiled:
-` + indent + `{{.Compiled}}
-
-{{end}}{{if len .Authors}}Author{{with $length := len .Authors}}{{if ne 1 $length}}s{{end}}{{end}}:{{range .Authors}}
-` + indent + `{{.}}{{end}}
-
-{{end}}{{if .Copyright}}Copyright:
-` + indent + `{{.Copyright}}
-
-{{end}}`
-)
-
 // Add words to this map if pluralization does not just involve adding an s.
 var plurals = map[string]string{
 	"policy": "policies",
diff --git a/cmd/helper.go b/cmd/helper.go
deleted file mode 100644
index 77f6b2f..0000000
--- a/cmd/helper.go
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * helper.go - Helper functions for using the cmd package
- *
- * Copyright 2017 Google Inc.
- * Author: Joe Richey (joerichey@google.com)
- *
- * 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 cmd
diff --git a/cmd/info.go b/cmd/info.go
deleted file mode 100644
index 96079ea..0000000
--- a/cmd/info.go
+++ /dev/null
@@ -1,96 +0,0 @@
-/*
- * info.go - Global information about the program.
- *
- * Copyright 2017 Google Inc.
- * Author: Joe Richey (joerichey@google.com)
- *
- * 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 cmd
-
-import (
-	"time"
-
-	"github.com/blang/semver"
-	"github.com/pkg/errors"
-)
-
-var (
-	// VersionTag (if set) will be displayed in both the short and long
-	// version output and can be accessed though Context.Info.Version.
-	// VersionTag must be formatted using Semver (http://semver.org/).
-	//
-	// Often set in Makefile with "-X cmd.VersionTag=$(VERSION)"
-	VersionTag string
-	// BuildTimeTag (if set) will be displayed in the long version
-	// output and can be accessed thought Context.Info.BuildTime. This
-	// string must be formatted as the output of UNIX `date`.
-	//
-	// Often set in Makefile with "-X cmd.BuildTimeTag=$(shell date)"
-	BuildTimeTag string
-	// Authors (if non-empty) are displayed in the long version output and
-	// can be accessed though Context.Info.Authors.
-	Authors []Author
-	// Copyright (if set) is displayed in the long version output and can
-	// be accessed through Context.Info.Copyright.
-	Copyright string
-)
-
-// fscrypt specific initialization
-func init() {
-	Authors = []Author{{
-		Name:  "Joe Richey",
-		Email: "joerichey@google.com",
-	}}
-	Copyright = `Copyright 2017 Google, Inc.
-
-	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.`
-}
-
-// Creates the Info structure by parsing the above global variables. Panics if
-// the variables to parse are in the incorrect format.
-func parseInfo() *Info {
-	var err error
-
-	var t time.Time
-	if BuildTimeTag != "" {
-		if t, err = time.Parse(time.UnixDate, BuildTimeTag); err != nil {
-			panic(err)
-		}
-	}
-
-	var v semver.Version
-	if VersionTag != "" {
-		if v, err = semver.ParseTolerant(VersionTag); err != nil {
-			panic(errors.Wrapf(err, "semver: parsing %q", VersionTag))
-		}
-	}
-
-	return &Info{
-		Version:   v,
-		BuildTime: t,
-		Authors:   Authors,
-		Copyright: Copyright,
-	}
-}
diff --git a/cmd/run.go b/cmd/run.go
new file mode 100644
index 0000000..a23de2d
--- /dev/null
+++ b/cmd/run.go
@@ -0,0 +1,199 @@
+/*

+ * run.go - Functions to setup and run Command Actions.

+ *

+ * Copyright 2017 Google Inc.

+ * Author: Joe Richey (joerichey@google.com)

+ *

+ * 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 cmd

+

+import (

+	"flag"

+	"fmt"

+	"io/ioutil"

+	"log"

+	"os"

+)

+

+var (

+	// HelpAction is performed whenever a Command uses the HelpFlag.

+	HelpAction Action = func(ctx *Context) error {

+		ExecuteTemplate(os.Stdout, TemplateTitle, ctx)

+		ExecuteTemplate(os.Stdout, TemplateUsage, ctx)

+		return nil

+	}

+	// DefaultAction is preformed when a Command has no Action specified.

+	DefaultAction = HelpAction

+	// stopFlag indicates that everything after the flag is an argument, not

+	// a command or flag.

+	stopFlag = "--"

+)

+

+// TemplateTitle describes the format of a Command's one line title.

+var TemplateTitle = "{{.FullName}}{{if .Command.Title}} - {{.Command.Title}}{{end}}\n"

+

+// TemplateUsage describes the format of a Command's usage.

+var TemplateUsage = `{{with $lines := .Command.UsageLines}}

+Usage:

+{{- range $lines}}

+	{{$.FullName}} {{. -}}

+{{end}}

+{{end -}}

+

+{{with $commands := .Command.SubCommands}}

+Commands:

+{{- range $commands}}

+	{{.Name}}{{if .Title}}	- {{.Title}}{{end -}}

+{{end}}

+{{end -}}

+

+{{with $arguments := .FullArguments}}

+Arguments:

+{{- range $arguments}}

+	{{.}}

+		{{wrapText .Usage 2 -}}

+{{end}}

+{{end -}}

+

+{{with $flags := .FullFlags}}

+Options:

+{{- range $flags}}

+	{{.}}

+		{{wrapText .FullUsage 2 -}}

+{{end}}

+{{end -}}

+

+{{with .ManPage}}

+For more information, see {{.}}.

+{{end -}}

+`

+

+// Divide the arguments into flag arguments (those starting with "-") and normal

+// arguments. If "--" appears in the list, it will classified as a normal

+// argument as well as all arguments following it. Also removes empty args.

+func sortArgs(args []string) (normalArgs, flagArgs []string) {

+	var arg string

+	for len(args) > 0 {

+		arg, args = args[0], args[1:]

+		if arg == "" {

+			continue

+		}

+		if arg == stopFlag {

+			normalArgs = append(normalArgs, arg)

+			normalArgs = append(normalArgs, args...)

+			return

+		} else if arg[0] == '-' {

+			flagArgs = append(flagArgs, arg)

+		} else {

+			normalArgs = append(normalArgs, arg)

+		}

+	}

+	return

+}

+

+// Returns the name of the requested sub-command or empty string (if a

+// sub-command was not requested).

+func subCommandName(ctx *Context) string {

+	// We must have actual arguments and subcommands to run a sub-command.

+	if len(ctx.Command.SubCommands) == 0 || len(ctx.Args) == 0 {

+		return ""

+	}

+	name := ctx.Args[0]

+	if name == stopFlag {

+		return ""

+	}

+	return name

+}

+

+// Returns the appropriate child context with a sub-command whose name matches

+// the provided name. If no sub-commands match the provied name, handle the

+// appropriate error and do not return.

+func getSubContext(ctx *Context, name string) *Context {

+	for _, subCommand := range ctx.Command.SubCommands {

+		if subCommand.Name == name {

+			return &Context{

+				Command:  subCommand,

+				Parent:   ctx,

+				Args:     ctx.Args[1:],

+				flagArgs: ctx.flagArgs,

+			}

+		}

+	}

+	ctx.processError(UsageError(fmt.Sprintf("unknown command %q", name)))

+	return nil

+}

+

+// Configures the Output and log output io.Writers. Called before running

+// commands but after processing flags.

+func setupOutput() {

+	if VerboseFlag.Value {

+		log.SetOutput(os.Stdout)

+	} else {

+		log.SetOutput(ioutil.Discard)

+	}

+	if Output != nil {

+		return

+	}

+	if QuietFlag.Value {

+		Output = ioutil.Discard

+	} else {

+		Output = os.Stdout

+	}

+}

+

+// Remove the stopFlag from the args if it is present. Args are modified

+// in-place and the correctly sized slice is returned.

+func setupArgs(args []string) []string {

+	for i, arg := range args {

+		if arg == stopFlag {

+			return append(args[:i], args[i+1:]...)

+		}

+	}

+	return args

+}

+

+// Return a command's action, the HelpAction, or DefaultAction.

+func getAction(cmd *Command) Action {

+	if HelpFlag.Value {

+		return HelpAction

+	}

+	if cmd.Action == nil {

+		return DefaultAction

+	}

+	return cmd.Action

+}

+

+func (ctx *Context) run() {

+	if name := subCommandName(ctx); name != "" {

+		getSubContext(ctx, name).run()

+		return

+	}

+

+	flagSet := flag.NewFlagSet("", flag.ContinueOnError)

+	flagSet.SetOutput(ioutil.Discard)

+	for _, flag := range ctx.FullFlags() {

+		flag.Apply(flagSet)

+	}

+	if err := flagSet.Parse(ctx.flagArgs); err != nil {

+		ctx.processError(err)

+		return

+	}

+

+	setupOutput()

+	ctx.Args = setupArgs(ctx.Args)

+	action := getAction(ctx.Command)

+

+	ctx.processError(action(ctx))

+}

diff --git a/cmd/strings.go b/cmd/strings.go
deleted file mode 100644
index 16c80f2..0000000
--- a/cmd/strings.go
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * strings.go - Strings and templates for output formatting
- *
- * Copyright 2017 Google Inc.
- * Author: Joe Richey (joerichey@google.com)
- *
- * 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 cmd
diff --git a/cmd/version.go b/cmd/version.go
index 99097b5..219684d 100644
--- a/cmd/version.go
+++ b/cmd/version.go
@@ -21,33 +21,89 @@ package cmd
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/blang/semver"
+	"github.com/pkg/errors"
 )
 
-// Templates for use with the version command, which both parse the Info var.
-var (
-	VersionTemplate     = "{{.FullName}} {{.Info.Version}}\n"
-	VersionLongTemplate = `{{if .Info.BuildTime}}
-Compiled:
-	{{.Info.BuildTime}}
-{{end}}
+// Info contains global information about the program.
+var Info = &InfoData{}
 
-{{with $length := len .Info.Authors}}
-{{if $length}}
-Author{{if ne 1 $length}}s{{end}}:
-{{range .Info.Authors}}
-	{{.Name}}{{if .Email}} <{{.Email}}>{{end}}
-{{end}}
-{{end}}
-{{end}}
+// InfoData describes the structure of our global program information
+type InfoData struct {
+	// Version (if set) will be displayed in both the short and long version
+	// output. This can be set directly or using VersionTag at link time.
+	Version semver.Version
+	// BuildTime (if set) will be displayed in the long version output. This
+	// can be set directory or by setting cmd.BuildTimeTag in a linking
+	// flag. s
+	//
+	BuildTime time.Time
+	// Authors (if non-empty) are displayed in the long version output.
+	Authors []Author
+	// Copyright (if set) is displayed in the long version output.
+	Copyright string
+}
 
-{{if .Info.Copyright}}
-Copyright:
-{{.Info.Copyright}}
-{{end}}`
+// Author contains the contact information for a contributor.
+type Author struct {
+	Name  string
+	Email string
+}
+
+// We have to use separate Tag variables, because build tags of the form:
+//	"-X cmd.Info.Version=foo"
+// are invalid.
+var (
+	// VersionTag can be set via the linker, and its value will be used to
+	// set Info.Version. Format this tag using Semver (http://semver.org/).
+	// Example:
+	//	"-X cmd.VersionTag=1.2.3-beta"
+	VersionTag string
+	// BuildTimeTag can be set via the linker, and its value will be used to
+	// set Info.BuildTime. Format this tag like the output of UNIX's `date`.
+	// Example:
+	//	"-X cmd.BuildTimeTag=Thu Oct 12 21:32:02 PDT 2017"
+	BuildTimeTag string
 )
 
+func init() {
+	var err error
+	// parse the tag variables
+	if VersionTag != "" {
+		Info.Version, err = semver.ParseTolerant(VersionTag)
+		if err != nil {
+			panic(errors.Wrapf(err, "semver: parsing %q", VersionTag))
+		}
+	}
+	if BuildTimeTag != "" {
+		Info.BuildTime, err = time.Parse(time.UnixDate, BuildTimeTag)
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	// fscrypt specific initialization
+	Info.Authors = []Author{{
+		Name:  "Joe Richey",
+		Email: "joerichey@google.com",
+	}}
+	Info.Copyright = `Copyright 2017 Google, Inc.
+
+	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.`
+}
+
 // VersionCommand is a command which will display either the VersionTag (by
 // default) or the full version information: version, copyright, authors, etc...
 var VersionCommand = &Command{
@@ -67,13 +123,34 @@ var longFlag = &BoolFlag{
 	Usage: "Print the detailed version, build, and copyright information.",
 }
 
+// TemplateVersionShort describes the format of the one line version command.
+var TemplateVersionShort = "{{.FullName}} {{.Info.Version}}\n"
+
+// TemplateVersionLong describes the format of the additional version data.
+var TemplateVersionLong = `{{if not .Info.BuildTime.IsZero}}
+Compiled:
+	{{.Info.BuildTime}}
+{{end -}}
+
+{{with $length := len .Info.Authors}}
+Author{{if ne 1 $length}}s{{end}}:
+{{- range $.Info.Authors}}
+	{{.Name}}{{if .Email}} <{{.Email}}>{{end -}}
+{{end}}
+{{end -}}
+
+{{if .Info.Copyright}}
+Copyright:
+	{{.Info.Copyright}}
+{{end}}`
+
 func versionAction(ctx *Context) error {
-	if ctx.Info.Version.Equals(semver.Version{}) {
+	if Info.Version.Equals(semver.Version{}) {
 		return ErrUnknownVersion
 	}
-	ctx.executeTemplate(Output, VersionTemplate)
+	ExecuteTemplate(Output, TemplateVersionShort, ctx)
 	if longFlag.Value {
-		ctx.executeTemplate(Output, VersionLongTemplate)
+		ExecuteTemplate(Output, TemplateVersionLong, ctx)
 	}
 	return nil
 }
diff --git a/ext4/ext4.go b/ext4/ext4.go
index 80d229d..dcf8204 100644
--- a/ext4/ext4.go
+++ b/ext4/ext4.go
@@ -25,58 +25,50 @@ import (
 	"github.com/google/fscrypt/cmd"
 )
 
-// Arguments used with the ext4 enable/disable commands.
 var (
-	MountpointArg = &cmd.Argument{
+	mountpointArg = &cmd.Argument{
 		ArgName: "mountpoint",
 		Usage:   "the path to an ext4 filesystem's mountpoint",
 	}
-	DeviceArg = &cmd.Argument{
+	deviceArg = &cmd.Argument{
 		ArgName: "device",
 		Usage:   "the path to a device containing an ext4 filesystem",
 	}
-	Ext4Usage = fmt.Sprintf("(%s | %s) [options]", MountpointArg, DeviceArg)
+	ext4Usage = fmt.Sprintf("(%s | %s) [options]", mountpointArg, deviceArg)
 )
 
-// Commands for running the ext4 enable/disable commands.
-var ()
+func main() { ext4Command.Run() }
 
-var Ext4Command = &cmd.Command{
-	Title: "toggle ext4 filesystem encryption flag",
+var ext4Command = &cmd.Command{
+	Title: "manage ext4 encryption feature flag",
 	UsageLines: []string{
-		fmt.Sprintf("(enable | disable) %s", Ext4Usage),
+		fmt.Sprintf("enable %s", ext4Usage),
+		fmt.Sprintf("disable %s", ext4Usage),
 		cmd.VersionUsage,
 	},
-	SubCommands: []*cmd.Command{EnableCommand, DisableCommand, cmd.VersionCommand},
-	Arguments:   []*cmd.Argument{MountpointArg, DeviceArg},
+	SubCommands: []*cmd.Command{enableCommand, disableCommand, cmd.VersionCommand},
+	Arguments:   []*cmd.Argument{mountpointArg, deviceArg},
 	Flags:       []cmd.Flag{cmd.ForceFlag, cmd.VerboseFlag, cmd.HelpFlag},
-	ManPage: &cmd.ManPage{
-		Title:   "fscrypt-ext4",
-		Section: 8,
-	},
+	ManPage:     &cmd.ManPage{Name: "fscrypt-ext4", Section: 8},
 }
-
-var EnableCommand = &cmd.Command{
+var enableCommand = &cmd.Command{
 	Name:             "enable",
 	Title:            "turn on encryption for an ext4 filesystem",
-	UsageLines:       []string{Ext4Usage},
+	UsageLines:       []string{ext4Usage},
 	InheritArguments: true,
 	InheritFlags:     true,
-	Action:           func(ctx *cmd.Context) error { return toggleState(ctx, true) },
+	Action:           func(c *cmd.Context) error { return toggleState(c, true) },
 }
-
-var DisableCommand = &cmd.Command{
+var disableCommand = &cmd.Command{
 	Name:             "disable",
 	Title:            "turn off encryption for an ext4 filesystem",
-	UsageLines:       []string{Ext4Usage},
+	UsageLines:       []string{ext4Usage},
 	InheritArguments: true,
 	InheritFlags:     true,
-	Action:           func(ctx *cmd.Context) error { return toggleState(ctx, false) },
+	Action:           func(c *cmd.Context) error { return toggleState(c, false) },
 }
 
-func main() { Ext4Command.Run() }
-
-func toggleState(ctx *cmd.Context, enable bool) error {
+func toggleState(c *cmd.Context, enable bool) error {
 	fmt.Fprintf(cmd.Output, "Toggle value = %v", enable)
 	return nil
 }
diff --git a/ext4/feature_flag.go b/ext4/feature_flag.go
index ab618e2..58b3669 100644
--- a/ext4/feature_flag.go
+++ b/ext4/feature_flag.go
@@ -1,3 +1,5 @@
+// +build linux,cgo
+
 /*
  * feature_flag.go - Changes encryption flag for an ext4 filesystem.
  *