diff --git a/command.go b/command.go
index db60c3b..f3321fb 100644
--- a/command.go
+++ b/command.go
@@ -11,7 +11,7 @@ type Command struct {
 
 // options returns all available complete options for the given command
 // args are all except the last command line arguments relevant to the command
-func (c *Command) options(args []string) (options []string, only bool) {
+func (c *Command) options(args []string) (options []Option, only bool) {
 
 	// remove the first argument, which is the command name
 	args = args[1:]
@@ -19,7 +19,7 @@ func (c *Command) options(args []string) (options []string, only bool) {
 	// if prev has something that needs to follow it,
 	// it is the most relevant completion
 	if options, ok := c.Flags[last(args)]; ok && options.HasFollow {
-		return options.FollowsOptions, true
+		return options.follows(), true
 	}
 
 	sub, options, only := c.searchSub(args)
@@ -35,13 +35,13 @@ func (c *Command) options(args []string) (options []string, only bool) {
 
 	// add global available complete options
 	for flag := range c.Flags {
-		options = append(options, flag)
+		options = append(options, Arg(flag))
 	}
 
 	return
 }
 
-func (c *Command) searchSub(args []string) (sub string, all []string, only bool) {
+func (c *Command) searchSub(args []string) (sub string, all []Option, only bool) {
 	for i, arg := range args {
 		if cmd, ok := c.Sub[arg]; ok {
 			sub = arg
@@ -52,11 +52,10 @@ func (c *Command) searchSub(args []string) (sub string, all []string, only bool)
 	return "", nil, false
 }
 
-func (c *Command) subCommands() []string {
-	subs := make([]string, 0, len(c.Sub))
+func (c *Command) subCommands() []Option {
+	subs := make([]Option, 0, len(c.Sub))
 	for sub := range c.Sub {
-		subs = append(subs, sub)
+		subs = append(subs, Arg(sub))
 	}
 	return subs
 }
-
diff --git a/complete.go b/complete.go
index eedaa81..6345e63 100644
--- a/complete.go
+++ b/complete.go
@@ -13,23 +13,19 @@ const (
 
 type Completer struct {
 	Command
-	log func(format string, args ...interface{})
 }
 
 func New(c Command) *Completer {
-	return &Completer{
-		Command: c,
-		log:     logger(),
-	}
+	return &Completer{Command: c}
 }
 
 func (c *Completer) Complete() {
 	args := getLine()
-	c.log("Completing args: %s", args)
+	logger("Completing args: %s", args)
 
 	options := c.complete(args)
 
-	c.log("Completion: %s", options)
+	logger("Completion: %s", options)
 	output(options)
 }
 
@@ -38,13 +34,10 @@ func (c *Completer) complete(args []string) []string {
 	return c.chooseRelevant(last(args), all)
 }
 
-func (c *Completer) chooseRelevant(last string, list []string) (opts []string) {
-	if last == "" {
-		return list
-	}
+func (c *Completer) chooseRelevant(last string, list []Option) (options []string) {
 	for _, sub := range list {
-		if strings.HasPrefix(sub, last) {
-			opts = append(opts, sub)
+		if sub.Matches(last) {
+			options = append(options, sub.String())
 		}
 	}
 	return
diff --git a/complete_test.go b/complete_test.go
index 55934bd..3485a99 100644
--- a/complete_test.go
+++ b/complete_test.go
@@ -9,7 +9,9 @@ import (
 func TestCompleter_Complete(t *testing.T) {
 	t.Parallel()
 
-	os.Setenv(envDebug, "1")
+	if testing.Verbose() {
+		os.Setenv(envDebug, "1")
+	}
 
 	c := Completer{
 		Command: Command{
@@ -30,9 +32,9 @@ func TestCompleter_Complete(t *testing.T) {
 			Flags: map[string]FlagOptions{
 				"-h":       FlagNoFollow,
 				"-global1": FlagUnknownFollow,
+				"-o":       FlagFileFilter("./gocomplete/*.go"),
 			},
 		},
-		log: t.Logf,
 	}
 
 	allGlobals := []string{}
@@ -53,7 +55,7 @@ func TestCompleter_Complete(t *testing.T) {
 		},
 		{
 			args: "-",
-			want: []string{"-h", "-global1"},
+			want: []string{"-h", "-global1", "-o"},
 		},
 		{
 			args: "-h ",
@@ -77,11 +79,11 @@ func TestCompleter_Complete(t *testing.T) {
 		},
 		{
 			args: "sub1 ",
-			want: []string{"-flag1", "-flag2", "-h", "-global1"},
+			want: []string{"-flag1", "-flag2", "-h", "-global1", "-o"},
 		},
 		{
 			args: "sub2 ",
-			want: []string{"-flag2", "-flag3", "-h", "-global1"},
+			want: []string{"-flag2", "-flag3", "-h", "-global1", "-o"},
 		},
 		{
 			args: "sub1 -fl",
@@ -97,7 +99,7 @@ func TestCompleter_Complete(t *testing.T) {
 		},
 		{
 			args: "sub1 -flag2 ",
-			want: []string{"-flag1", "-flag2", "-h", "-global1"},
+			want: []string{"-flag1", "-flag2", "-h", "-global1", "-o"},
 		},
 		{
 			args: "-no-such-flag",
@@ -115,6 +117,18 @@ func TestCompleter_Complete(t *testing.T) {
 			args: "no-such-command ",
 			want: allGlobals,
 		},
+		{
+			args: "-o ",
+			want: []string{"./gocomplete/complete.go"},
+		},
+		{
+			args: "-o goco",
+			want: []string{"./gocomplete/complete.go"},
+		},
+		{
+			args: "-o ./goco",
+			want: []string{"./gocomplete/complete.go"},
+		},
 	}
 
 	for _, tt := range tests {
diff --git a/flag.go b/flag.go
index 2673c7a..645cb83 100644
--- a/flag.go
+++ b/flag.go
@@ -1,8 +1,20 @@
 package complete
 
+import (
+	"os"
+	"path/filepath"
+)
+
 type FlagOptions struct {
 	HasFollow      bool
-	FollowsOptions []string
+	FollowsOptions func() []Option
+}
+
+func (f *FlagOptions) follows() []Option {
+	if f.FollowsOptions == nil {
+		return nil
+	}
+	return f.FollowsOptions()
 }
 
 var (
@@ -10,3 +22,44 @@ var (
 	FlagUnknownFollow = FlagOptions{HasFollow: true}
 )
 
+func FlagFileFilter(pattern string) FlagOptions {
+	return FlagOptions{
+		HasFollow:      true,
+		FollowsOptions: glob(pattern),
+	}
+}
+
+func glob(pattern string) func() []Option {
+	return func() []Option {
+		files, err := filepath.Glob(pattern)
+		if err != nil {
+			logger("failed glob operation with pattern '%s': %s", pattern, err)
+		}
+		if !filepath.IsAbs(pattern) {
+			filesToRel(files)
+		}
+		options := make([]Option, len(files))
+		for i, f := range files {
+			options[i] = ArgFileName(f)
+		}
+		return options
+	}
+}
+func filesToRel(files []string) {
+	wd, err := os.Getwd()
+	if err != nil {
+		return
+	}
+	for i := range files {
+		abs, err := filepath.Abs(files[i])
+		if err != nil {
+			continue
+		}
+		rel, err := filepath.Rel(wd, abs)
+		if err != nil {
+			continue
+		}
+		files[i] = "./" + rel
+	}
+	return
+}
diff --git a/log.go b/log.go
index b3fdb8e..0b0a54a 100644
--- a/log.go
+++ b/log.go
@@ -7,8 +7,9 @@ import (
 	"os"
 )
 
+var logger = getLogger()
 
-func logger() func(format string, args ...interface{}) {
+func getLogger() func(format string, args ...interface{}) {
 	var logfile io.Writer = ioutil.Discard
 	if os.Getenv(envDebug) != "" {
 		logfile = os.Stderr
diff --git a/option.go b/option.go
new file mode 100644
index 0000000..9333e84
--- /dev/null
+++ b/option.go
@@ -0,0 +1,39 @@
+package complete
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+type Option interface {
+	String() string
+	Matches(prefix string) bool
+}
+
+type Arg string
+
+func (a Arg) String() string {
+	return string(a)
+}
+
+func (a Arg) Matches(prefix string) bool {
+	return strings.HasPrefix(string(a), prefix)
+}
+
+type ArgFileName string
+
+func (a ArgFileName) String() string {
+	return string(a)
+}
+
+func (a ArgFileName) Matches(prefix string) bool {
+	full, err := filepath.Abs(string(a))
+	if err != nil {
+		logger("failed getting abs path of %s: %s", a, err)
+	}
+	prefixFull, err := filepath.Abs(prefix)
+	if err != nil {
+		logger("failed getting abs path of %s: %s", prefix, err)
+	}
+	return strings.HasPrefix(full, prefixFull)
+}