diff --git a/cmd/remove.go b/cmd/remove.go
index d7df9e3..91fb69e 100644
--- a/cmd/remove.go
+++ b/cmd/remove.go
@@ -4,12 +4,10 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"runtime"
-	"strings"
 
 	"github.com/spf13/cobra"
 
-	"github.com/Akimon658/gup/internal/file"
+	"github.com/Akimon658/gup/file"
 	"github.com/Akimon658/gup/internal/goutil"
 	"github.com/Akimon658/gup/internal/print"
 )
@@ -44,14 +42,18 @@ func remove(args []string, force bool) int {
 
 	code := 0
 	for _, v := range args {
-		if runtime.GOOS == "windows" && !strings.HasSuffix(v, ".exe") {
-			v += ".exe"
-		}
+		v = file.Extension(v)
 
 		target := filepath.Join(gobin, v)
+		stat, err := os.Stat(target)
+		if err != nil {
+			print.Err(err)
+			code = 1
+			continue
+		}
 
-		if !file.IsFile(target) {
-			print.Err(fmt.Errorf("no such file or directory: %s", target))
+		if stat.IsDir() {
+			print.Err(fmt.Errorf("no such file: %s", target))
 			code = 1
 			continue
 		}
diff --git a/cmd/update.go b/cmd/update.go
index 7c39303..f8b5b4c 100644
--- a/cmd/update.go
+++ b/cmd/update.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"github.com/Akimon658/gup/file"
 	"github.com/Akimon658/gup/internal/goutil"
 	"github.com/Akimon658/gup/internal/print"
 	"github.com/Akimon658/gup/internal/slice"
@@ -164,10 +165,14 @@ func extractUserSpecifyPkg(pkgs []goutil.Package, targets []string) []goutil.Pac
 	if len(targets) == 0 {
 		return pkgs
 	}
-	for _, v := range pkgs {
-		if slice.Contains(targets, v.Name) {
-			result = append(result, v)
-			tmp = append(tmp, v.Name)
+
+	for _, v := range targets {
+		v = file.Extension(v)
+		for _, w := range pkgs {
+			if v == w.Name {
+				result = append(result, w)
+				tmp = append(tmp, w.Name)
+			}
 		}
 	}
 
@@ -178,5 +183,6 @@ func extractUserSpecifyPkg(pkgs []goutil.Package, targets []string) []goutil.Pac
 			}
 		}
 	}
+
 	return result
 }
diff --git a/file/extension.go b/file/extension.go
new file mode 100644
index 0000000..ea2d253
--- /dev/null
+++ b/file/extension.go
@@ -0,0 +1,16 @@
+package file
+
+import (
+	"runtime"
+	"strings"
+)
+
+const extWin = ".exe"
+
+func Extension(name string) string {
+	if runtime.GOOS == "windows" && !strings.HasSuffix(name, extWin) {
+		name += extWin
+	}
+
+	return name
+}
diff --git a/file/extension_test.go b/file/extension_test.go
new file mode 100644
index 0000000..2d0e44c
--- /dev/null
+++ b/file/extension_test.go
@@ -0,0 +1,44 @@
+package file
+
+import (
+	"runtime"
+	"testing"
+
+	"github.com/jaswdr/faker"
+)
+
+func TestExtension(t *testing.T) {
+	fileName := faker.New().Lorem().Word()
+	fileNameWithExtension := fileName + extWin
+	testCases := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "without extension",
+			input:    fileName,
+			expected: fileNameWithExtension,
+		},
+		{
+			name:     "with extension",
+			input:    fileNameWithExtension,
+			expected: fileNameWithExtension,
+		},
+	}
+
+	for _, v := range testCases {
+		t.Run(v.name, func(t *testing.T) {
+			result := Extension(v.input)
+			if runtime.GOOS == "windows" {
+				if result != v.expected {
+					t.Errorf("expected %s, got %s", v.expected, result)
+				}
+			} else {
+				if result != v.input {
+					t.Errorf("expected %s, got %s", v.input, result)
+				}
+			}
+		})
+	}
+}
diff --git a/internal/file/file.go b/internal/file/file.go
deleted file mode 100644
index d079e8b..0000000
--- a/internal/file/file.go
+++ /dev/null
@@ -1,42 +0,0 @@
-package file
-
-import (
-	"bufio"
-	"io"
-	"os"
-)
-
-// ReadFileToList convert file content to string list.
-func ReadFileToList(path string) ([]string, error) {
-	var strList []string
-	f, err := os.Open(path)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	r := bufio.NewReader(f)
-	for {
-		line, err := r.ReadString('\n')
-		if err != nil && err != io.EOF {
-			return nil, err
-		}
-		if err == io.EOF && len(line) == 0 {
-			break
-		}
-		strList = append(strList, line)
-	}
-	return strList, nil
-}
-
-// IsFile reports whether the path exists and is a file.
-func IsFile(path string) bool {
-	stat, err := os.Stat(path)
-	return (err == nil) && (!stat.IsDir())
-}
-
-// IsDir reports whether the path exists and is a directory.
-func IsDir(path string) bool {
-	stat, err := os.Stat(path)
-	return (err == nil) && (stat.IsDir())
-}