diff --git a/.gitignore b/.gitignore
index 6f7e308..b0326bd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,5 @@ _testmain.go
 *.prof
 
 .DS_Store
+
+.vscode
diff --git a/filelist.go b/filelist.go
index 86e144c..3280edd 100644
--- a/filelist.go
+++ b/filelist.go
@@ -15,60 +15,58 @@
 package main
 
 import (
-	"fmt"
-	"os"
-	"path/filepath"
+	"log"
 	"strings"
+
+	"github.com/ryanuber/go-glob"
 )
 
-type filelist struct {
-	paths map[string]bool
-	globs []string
+// fileList uses a map for patterns to ensure each pattern only
+// appears once
+type fileList struct {
+	patterns map[string]struct{}
 }
 
-func newFileList(paths ...string) *filelist {
-
-	f := &filelist{
-		make(map[string]bool),
-		make([]string, 0),
+func newFileList(paths ...string) *fileList {
+	f := &fileList{
+		patterns: make(map[string]struct{}),
 	}
-
-	for _, path := range paths {
-		if e := f.Set(path); e != nil {
-			// #nosec
-			fmt.Fprintf(os.Stderr, "Unable to add %s to filelist: %s\n", path, e)
-		}
+	for _, p := range paths {
+		f.patterns[p] = struct{}{}
 	}
 	return f
 }
 
-func (f *filelist) String() string {
-	return strings.Join(f.globs, ", ")
+func (f *fileList) String() string {
+	ps := make([]string, 0, len(f.patterns))
+	for p := range f.patterns {
+		ps = append(ps, p)
+	}
+	return strings.Join(ps, ", ")
 }
 
-func (f *filelist) Set(path string) error {
-	f.globs = append(f.globs, path)
-	matches, e := filepath.Glob(path)
-	if e != nil {
-		return e
-	}
-	for _, each := range matches {
-		abs, e := filepath.Abs(each)
-		if e != nil {
-			return e
-		}
-		f.paths[abs] = true
+func (f *fileList) Set(path string) error {
+	if path == "" {
+		// don't bother adding the empty path
+		return nil
 	}
+	f.patterns[path] = struct{}{}
 	return nil
 }
 
-func (f filelist) Contains(path string) bool {
-	_, present := f.paths[path]
-	return present
+func (f fileList) Contains(path string) bool {
+	for p := range f.patterns {
+		if glob.Glob(p, path) {
+			log.Printf("excluding: %s\n", path)
+			return true
+		}
+	}
+	log.Printf("including: %s\n", path)
+	return false
 }
 
 /*
-func (f filelist) Dump() {
+func (f fileList) Dump() {
 	for k, _ := range f.paths {
 		println(k)
 	}
diff --git a/filelist_test.go b/filelist_test.go
new file mode 100644
index 0000000..61421fa
--- /dev/null
+++ b/filelist_test.go
@@ -0,0 +1,245 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func Test_newFileList(t *testing.T) {
+	type args struct {
+		paths []string
+	}
+	tests := []struct {
+		name string
+		args args
+		want *fileList
+	}{
+		{
+			name: "nil paths",
+			args: args{paths: nil},
+			want: &fileList{patterns: map[string]struct{}{}},
+		},
+		{
+			name: "empty paths",
+			args: args{paths: []string{}},
+			want: &fileList{patterns: map[string]struct{}{}},
+		},
+		{
+			name: "have paths",
+			args: args{paths: []string{"*_test.go"}},
+			want: &fileList{patterns: map[string]struct{}{
+				"*_test.go": struct{}{},
+			}},
+		},
+	}
+	for _, tt := range tests {
+		if got := newFileList(tt.args.paths...); !reflect.DeepEqual(got, tt.want) {
+			t.Errorf("%q. newFileList() = %v, want %v", tt.name, got, tt.want)
+		}
+	}
+}
+
+func Test_fileList_String(t *testing.T) {
+	type fields struct {
+		patterns []string
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   string
+	}{
+		{
+			name:   "nil patterns",
+			fields: fields{patterns: nil},
+			want:   "",
+		},
+		{
+			name:   "empty patterns",
+			fields: fields{patterns: []string{}},
+			want:   "",
+		},
+		{
+			name:   "one pattern",
+			fields: fields{patterns: []string{"foo"}},
+			want:   "foo",
+		},
+		{
+			name:   "two patterns",
+			fields: fields{patterns: []string{"foo", "bar"}},
+			want:   "foo, bar",
+		},
+	}
+	for _, tt := range tests {
+		f := newFileList(tt.fields.patterns...)
+		if got := f.String(); got != tt.want {
+			t.Errorf("%q. fileList.String() = %v, want %v", tt.name, got, tt.want)
+		}
+	}
+}
+
+func Test_fileList_Set(t *testing.T) {
+	type fields struct {
+		patterns []string
+	}
+	type args struct {
+		path string
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		args    args
+		want    map[string]struct{}
+		wantErr bool
+	}{
+		{
+			name:    "add empty path",
+			fields:  fields{patterns: nil},
+			args:    args{path: ""},
+			want:    map[string]struct{}{},
+			wantErr: false,
+		},
+		{
+			name:   "add path to nil patterns",
+			fields: fields{patterns: nil},
+			args:   args{path: "foo"},
+			want: map[string]struct{}{
+				"foo": struct{}{},
+			},
+			wantErr: false,
+		},
+		{
+			name:   "add path to empty patterns",
+			fields: fields{patterns: []string{}},
+			args:   args{path: "foo"},
+			want: map[string]struct{}{
+				"foo": struct{}{},
+			},
+			wantErr: false,
+		},
+		{
+			name:   "add path to populated patterns",
+			fields: fields{patterns: []string{"foo"}},
+			args:   args{path: "bar"},
+			want: map[string]struct{}{
+				"foo": struct{}{},
+				"bar": struct{}{},
+			},
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		f := newFileList(tt.fields.patterns...)
+		if err := f.Set(tt.args.path); (err != nil) != tt.wantErr {
+			t.Errorf("%q. fileList.Set() error = %v, wantErr %v", tt.name, err, tt.wantErr)
+		}
+		if !reflect.DeepEqual(f.patterns, tt.want) {
+			t.Errorf("%q. got state fileList.patterns = %v, want state %v", tt.name, f.patterns, tt.want)
+		}
+	}
+}
+
+func Test_fileList_Contains(t *testing.T) {
+	type fields struct {
+		patterns []string
+	}
+	type args struct {
+		path string
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   bool
+	}{
+		{
+			name:   "nil patterns",
+			fields: fields{patterns: nil},
+			args:   args{path: "foo"},
+			want:   false,
+		},
+		{
+			name:   "empty patterns",
+			fields: fields{patterns: nil},
+			args:   args{path: "foo"},
+			want:   false,
+		},
+		{
+			name:   "one pattern, no wildcard, no match",
+			fields: fields{patterns: []string{"foo"}},
+			args:   args{path: "bar"},
+			want:   false,
+		},
+		{
+			name:   "one pattern, no wildcard, match",
+			fields: fields{patterns: []string{"foo"}},
+			args:   args{path: "foo"},
+			want:   true,
+		},
+		{
+			name:   "one pattern, wildcard prefix, match",
+			fields: fields{patterns: []string{"*foo"}},
+			args:   args{path: "foo"},
+			want:   true,
+		},
+		{
+			name:   "one pattern, wildcard suffix, match",
+			fields: fields{patterns: []string{"foo*"}},
+			args:   args{path: "foo"},
+			want:   true,
+		},
+		{
+			name:   "one pattern, wildcard both ends, match",
+			fields: fields{patterns: []string{"*foo*"}},
+			args:   args{path: "foo"},
+			want:   true,
+		},
+		{
+			name:   "default test match 1",
+			fields: fields{patterns: []string{"*_test.go"}},
+			args:   args{path: "foo_test.go"},
+			want:   true,
+		},
+		{
+			name:   "default test match 2",
+			fields: fields{patterns: []string{"*_test.go"}},
+			args:   args{path: "bar/foo_test.go"},
+			want:   true,
+		},
+		{
+			name:   "default test match 3",
+			fields: fields{patterns: []string{"*_test.go"}},
+			args:   args{path: "/bar/foo_test.go"},
+			want:   true,
+		},
+		{
+			name:   "default test match 4",
+			fields: fields{patterns: []string{"*_test.go"}},
+			args:   args{path: "baz/bar/foo_test.go"},
+			want:   true,
+		},
+		{
+			name:   "default test match 5",
+			fields: fields{patterns: []string{"*_test.go"}},
+			args:   args{path: "/baz/bar/foo_test.go"},
+			want:   true,
+		},
+		{
+			name:   "many patterns, no match",
+			fields: fields{patterns: []string{"*_one.go", "*_two.go"}},
+			args:   args{path: "/baz/bar/foo_test.go"},
+			want:   false,
+		},
+		{
+			name:   "many patterns, match",
+			fields: fields{patterns: []string{"*_one.go", "*_two.go", "*_test.go"}},
+			args:   args{path: "/baz/bar/foo_test.go"},
+			want:   true,
+		},
+	}
+	for _, tt := range tests {
+		f := newFileList(tt.fields.patterns...)
+		if got := f.Contains(tt.args.path); got != tt.want {
+			t.Errorf("%q. fileList.Contains() = %v, want %v", tt.name, got, tt.want)
+		}
+	}
+}
diff --git a/main.go b/main.go
index 248f548..8686060 100644
--- a/main.go
+++ b/main.go
@@ -29,22 +29,30 @@ import (
 	"github.com/GoASTScanner/gas/output"
 )
 
-// #nosec flag
-var flagIgnoreNoSec = flag.Bool("nosec", false, "Ignores #nosec comments when set")
+type recursion bool
 
-// format output
-var flagFormat = flag.String("fmt", "text", "Set output format. Valid options are: json, csv, html, or text")
+const (
+	recurse   recursion = true
+	noRecurse recursion = false
+)
 
-// output file
-var flagOutput = flag.String("out", "", "Set output file for results")
+var (
+	// #nosec flag
+	flagIgnoreNoSec = flag.Bool("nosec", false, "Ignores #nosec comments when set")
 
-// config file
-var flagConfig = flag.String("conf", "", "Path to optional config file")
+	// format output
+	flagFormat = flag.String("fmt", "text", "Set output format. Valid options are: json, csv, html, or text")
 
-// quiet
-var flagQuiet = flag.Bool("quiet", false, "Only show output when errors are found")
+	// output file
+	flagOutput = flag.String("out", "", "Set output file for results")
 
-var usageText = `
+	// config file
+	flagConfig = flag.String("conf", "", "Path to optional config file")
+
+	// quiet
+	flagQuiet = flag.Bool("quiet", false, "Only show output when errors are found")
+
+	usageText = `
 GAS - Go AST Scanner
 
 Gas analyzes Go source code to look for common programming mistakes that
@@ -67,7 +75,8 @@ USAGE:
 
 `
 
-var logger *log.Logger
+	logger *log.Logger
+)
 
 func extendConfList(conf map[string]interface{}, name string, inputStr string) {
 	if inputStr == "" {
@@ -145,7 +154,7 @@ func main() {
 	flag.Usage = usage
 
 	//  Exclude files
-	excluded := newFileList("**/*_test.go")
+	excluded := newFileList("*_test.go")
 	flag.Var(excluded, "skip", "File pattern to exclude from scan")
 
 	incRules := ""
@@ -183,42 +192,11 @@ func main() {
 	analyzer := gas.NewAnalyzer(config, logger)
 	AddRules(&analyzer, config)
 
-	// Traverse directory structure if './...'
-	if flag.NArg() == 1 && flag.Arg(0) == "./..." {
+	toAnalyze := getFilesToAnalyze(flag.Args(), excluded)
 
-		cwd, err := os.Getwd()
-		if err != nil {
-			logger.Fatalf("Unable to traverse path %s, reason - %s", flag.Arg(0), err)
-		}
-		filepath.Walk(cwd, func(path string, info os.FileInfo, err error) error {
-			if excluded.Contains(path) && info.IsDir() {
-				logger.Printf("Skipping %s\n", path)
-				return filepath.SkipDir
-			}
-			if !info.IsDir() && !excluded.Contains(path) &&
-				strings.HasSuffix(path, ".go") {
-				err = analyzer.Process(path)
-				if err != nil {
-					logger.Fatal(err)
-				}
-			}
-			return nil
-		})
-
-	} else {
-
-		// Process each file individually
-		for _, filename := range flag.Args() {
-			if finfo, err := os.Stat(filename); err == nil {
-				if !finfo.IsDir() && !excluded.Contains(filename) &&
-					strings.HasSuffix(filename, ".go") {
-					if err = analyzer.Process(filename); err != nil {
-						logger.Fatal(err)
-					}
-				}
-			} else {
-				logger.Fatal(err)
-			}
+	for _, file := range toAnalyze {
+		if err := analyzer.Process(file); err != nil {
+			logger.Fatal(err)
 		}
 	}
 
@@ -245,3 +223,68 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+// getFilesToAnalyze lists all files
+func getFilesToAnalyze(paths []string, excluded *fileList) []string {
+	log.Println("getFilesToAnalyze: start")
+	var toAnalyze []string
+	for _, path := range paths {
+		log.Printf("getFilesToAnalyze: processing \"%s\"\n", path)
+		// get the absolute path before doing anything else
+		path, err := filepath.Abs(path)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if filepath.Base(path) == "..." {
+			toAnalyze = append(
+				toAnalyze,
+				listFiles(filepath.Dir(path), recurse, excluded)...,
+			)
+		} else {
+			var (
+				finfo os.FileInfo
+				err   error
+			)
+			if finfo, err = os.Stat(path); err != nil {
+				logger.Fatal(err)
+			}
+			if !finfo.IsDir() {
+				if shouldInclude(path, excluded) {
+					toAnalyze = append(toAnalyze, path)
+				}
+			} else {
+				toAnalyze = listFiles(path, noRecurse, excluded)
+			}
+		}
+	}
+	log.Println("getFilesToAnalyze: end")
+	return toAnalyze
+}
+
+// listFiles returns a list of all files found that pass the shouldInclude check.
+// If doRecursiveWalk it true, it will walk the tree rooted at absPath, otherwise it
+// will only include files directly within the dir referenced by absPath.
+func listFiles(absPath string, doRecursiveWalk recursion, excluded *fileList) []string {
+	var files []string
+
+	walk := func(path string, info os.FileInfo, err error) error {
+		if info.IsDir() && doRecursiveWalk == noRecurse {
+			return filepath.SkipDir
+		}
+		if shouldInclude(path, excluded) {
+			files = append(files, path)
+		}
+		return nil
+	}
+
+	if err := filepath.Walk(absPath, walk); err != nil {
+		log.Fatal(err)
+	}
+	return files
+}
+
+// shouldInclude checks if a specific path which is expected to reference
+// a regular file should be included
+func shouldInclude(path string, excluded *fileList) bool {
+	return filepath.Ext(path) == ".go" && !excluded.Contains(path)
+}
diff --git a/main_test.go b/main_test.go
new file mode 100644
index 0000000..b47a4b5
--- /dev/null
+++ b/main_test.go
@@ -0,0 +1,45 @@
+package main
+
+import "testing"
+
+func Test_shouldInclude(t *testing.T) {
+	type args struct {
+		path     string
+		excluded *fileList
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "non .go file",
+			args: args{
+				path:     "thing.txt",
+				excluded: newFileList(),
+			},
+			want: false,
+		},
+		{
+			name: ".go file, not excluded",
+			args: args{
+				path:     "thing.go",
+				excluded: newFileList(),
+			},
+			want: true,
+		},
+		{
+			name: ".go file, excluded",
+			args: args{
+				path:     "thing.go",
+				excluded: newFileList("thing.go"),
+			},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		if got := shouldInclude(tt.args.path, tt.args.excluded); got != tt.want {
+			t.Errorf("%q. shouldInclude() = %v, want %v", tt.name, got, tt.want)
+		}
+	}
+}
diff --git a/vendor.conf b/vendor.conf
new file mode 100644
index 0000000..323514f
--- /dev/null
+++ b/vendor.conf
@@ -0,0 +1,2 @@
+# Import path             | revision                               | Repository(optional)
+github.com/ryanuber/go-glob 572520ed46dbddaed19ea3d9541bdd0494163693
diff --git a/vendor/github.com/ryanuber/go-glob/LICENSE b/vendor/github.com/ryanuber/go-glob/LICENSE
new file mode 100644
index 0000000..bdfbd95
--- /dev/null
+++ b/vendor/github.com/ryanuber/go-glob/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Ryan Uber
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/ryanuber/go-glob/glob.go b/vendor/github.com/ryanuber/go-glob/glob.go
new file mode 100644
index 0000000..d9d4637
--- /dev/null
+++ b/vendor/github.com/ryanuber/go-glob/glob.go
@@ -0,0 +1,51 @@
+package glob
+
+import "strings"
+
+// The character which is treated like a glob
+const GLOB = "*"
+
+// Glob will test a string pattern, potentially containing globs, against a
+// subject string. The result is a simple true/false, determining whether or
+// not the glob pattern matched the subject text.
+func Glob(pattern, subj string) bool {
+	// Empty pattern can only match empty subject
+	if pattern == "" {
+		return subj == pattern
+	}
+
+	// If the pattern _is_ a glob, it matches everything
+	if pattern == GLOB {
+		return true
+	}
+
+	parts := strings.Split(pattern, GLOB)
+
+	if len(parts) == 1 {
+		// No globs in pattern, so test for equality
+		return subj == pattern
+	}
+
+	leadingGlob := strings.HasPrefix(pattern, GLOB)
+	trailingGlob := strings.HasSuffix(pattern, GLOB)
+	end := len(parts) - 1
+
+	// Check the first section. Requires special handling.
+	if !leadingGlob && !strings.HasPrefix(subj, parts[0]) {
+		return false
+	}
+
+	// Go over the middle parts and ensure they match.
+	for i := 1; i < end; i++ {
+		if !strings.Contains(subj, parts[i]) {
+			return false
+		}
+
+		// Trim evaluated text from subj as we loop over the pattern.
+		idx := strings.Index(subj, parts[i]) + len(parts[i])
+		subj = subj[idx:]
+	}
+
+	// Reached the last section. Requires special handling.
+	return trailingGlob || strings.HasSuffix(subj, parts[end])
+}