diff --git a/app.go b/app.go
index 2f1fec9c..a95b1801 100644
--- a/app.go
+++ b/app.go
@@ -232,7 +232,7 @@ func (app *app) writeHistory() error {
 	}
 
 	for _, cmd := range app.cmdHistory {
-		_, err = f.WriteString(fmt.Sprintf("%s %s\n", cmd.prefix, cmd.value))
+		_, err = fmt.Fprintf(f, "%s %s\n", cmd.prefix, cmd.value)
 		if err != nil {
 			return fmt.Errorf("writing history file: %s", err)
 		}
@@ -585,5 +585,4 @@ func (app *app) runShell(s string, args []string, prefix string) {
 			app.ui.exprChan <- &callExpr{"load", nil, 1}
 		}()
 	}
-
 }
diff --git a/client.go b/client.go
index 559102d2..52360b49 100644
--- a/client.go
+++ b/client.go
@@ -38,7 +38,7 @@ func run() {
 	}
 
 	if gLogPath != "" {
-		f, err := os.OpenFile(gLogPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+		f, err := os.OpenFile(gLogPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0o600)
 		if err != nil {
 			panic(err)
 		}
diff --git a/colors.go b/colors.go
index 8558b3fa..2d5d8c9e 100644
--- a/colors.go
+++ b/colors.go
@@ -295,9 +295,9 @@ func (sm styleMap) get(f *file) tcell.Style {
 		key = "ln"
 	case f.linkState == broken:
 		key = "or"
-	case f.IsDir() && f.Mode()&os.ModeSticky != 0 && f.Mode()&0002 != 0:
+	case f.IsDir() && f.Mode()&os.ModeSticky != 0 && f.Mode()&0o002 != 0:
 		key = "tw"
-	case f.IsDir() && f.Mode()&0002 != 0:
+	case f.IsDir() && f.Mode()&0o002 != 0:
 		key = "ow"
 	case f.IsDir() && f.Mode()&os.ModeSticky != 0:
 		key = "st"
@@ -315,7 +315,7 @@ func (sm styleMap) get(f *file) tcell.Style {
 		key = "su"
 	case f.Mode()&os.ModeSetgid != 0:
 		key = "sg"
-	case f.Mode()&0111 != 0:
+	case f.Mode()&0o111 != 0:
 		key = "ex"
 	}
 
diff --git a/copy.go b/copy.go
index ea848111..cec83c28 100644
--- a/copy.go
+++ b/copy.go
@@ -20,14 +20,13 @@ func copySize(srcs []string) (int64, error) {
 			return total, fmt.Errorf("src does not exist: %q", src)
 		}
 
-		err = filepath.Walk(src, func(path string, info os.FileInfo, err error) error {
+		err = filepath.Walk(src, func(_ string, info os.FileInfo, err error) error {
 			if err != nil {
 				return fmt.Errorf("walk: %s", err)
 			}
 			total += info.Size()
 			return nil
 		})
-
 		if err != nil {
 			return total, err
 		}
diff --git a/icons.go b/icons.go
index 963a7a2e..49a522ab 100644
--- a/icons.go
+++ b/icons.go
@@ -147,9 +147,9 @@ func (im iconMap) get(f *file) iconDef {
 		key = "ln"
 	case f.linkState == broken:
 		key = "or"
-	case f.IsDir() && f.Mode()&os.ModeSticky != 0 && f.Mode()&0002 != 0:
+	case f.IsDir() && f.Mode()&os.ModeSticky != 0 && f.Mode()&0o002 != 0:
 		key = "tw"
-	case f.IsDir() && f.Mode()&0002 != 0:
+	case f.IsDir() && f.Mode()&0o002 != 0:
 		key = "ow"
 	case f.IsDir() && f.Mode()&os.ModeSticky != 0:
 		key = "st"
@@ -167,7 +167,7 @@ func (im iconMap) get(f *file) iconDef {
 		key = "su"
 	case f.Mode()&os.ModeSetgid != 0:
 		key = "sg"
-	case f.Mode()&0111 != 0:
+	case f.Mode()&0o111 != 0:
 		key = "ex"
 	}
 
diff --git a/misc_test.go b/misc_test.go
index f991c3a5..f4095603 100644
--- a/misc_test.go
+++ b/misc_test.go
@@ -330,7 +330,7 @@ func TestGetFileExtension(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			if got := getFileExtension(fakeFileInfo{test.fileName, test.isDir}); got != test.expectedExtension {
-				t.Errorf("at input %q expected %q but got %q", test.fileName, test.expectedExtension, got)
+				t.Errorf("at input '%s' expected '%s' but got '%s'", test.fileName, test.expectedExtension, got)
 			}
 		})
 	}
diff --git a/nav.go b/nav.go
index 0a16cfbb..dc95498e 100644
--- a/nav.go
+++ b/nav.go
@@ -1884,7 +1884,7 @@ func (nav *nav) writeMarks() error {
 	sort.Strings(keys)
 
 	for _, k := range keys {
-		_, err = f.WriteString(fmt.Sprintf("%s:%s\n", k, nav.marks[k]))
+		_, err = fmt.Fprintf(f, "%s:%s\n", k, nav.marks[k])
 		if err != nil {
 			return fmt.Errorf("writing marks file: %s", err)
 		}
@@ -1945,7 +1945,7 @@ func (nav *nav) writeTags() error {
 	sort.Strings(keys)
 
 	for _, k := range keys {
-		_, err = f.WriteString(fmt.Sprintf("%s:%s\n", k, nav.tags[k]))
+		_, err = fmt.Fprintf(f, "%s:%s\n", k, nav.tags[k])
 		if err != nil {
 			return fmt.Errorf("writing tags file: %s", err)
 		}
diff --git a/os.go b/os.go
index 962bb418..0a35f1c2 100644
--- a/os.go
+++ b/os.go
@@ -177,11 +177,11 @@ func setDefaults() {
 }
 
 func setUserUmask() {
-	unix.Umask(0077)
+	unix.Umask(0o077)
 }
 
 func isExecutable(f os.FileInfo) bool {
-	return f.Mode()&0111 != 0
+	return f.Mode()&0o111 != 0
 }
 
 func isHidden(f os.FileInfo, path string, hiddenfiles []string) bool {
diff --git a/server.go b/server.go
index b278b133..7bb6e73f 100644
--- a/server.go
+++ b/server.go
@@ -17,7 +17,7 @@ var (
 
 func serve() {
 	if gLogPath != "" {
-		f, err := os.OpenFile(gLogPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+		f, err := os.OpenFile(gLogPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0o600)
 		if err != nil {
 			panic(err)
 		}
diff --git a/ui.go b/ui.go
index 0a26c2ed..f7684ece 100644
--- a/ui.go
+++ b/ui.go
@@ -293,27 +293,27 @@ func fileInfo(f *file, d *dir) string {
 	for _, s := range getInfo(d.path) {
 		switch s {
 		case "size":
-			if !(f.IsDir() && gOpts.dircounts) {
-				var sz string
-				if f.IsDir() && f.dirSize < 0 {
-					sz = "-"
-				} else {
-					sz = humanize(f.TotalSize())
+			if f.IsDir() && gOpts.dircounts {
+				switch {
+				case f.dirCount < -1:
+					info = fmt.Sprintf("%s    !", info)
+				case f.dirCount < 0:
+					info = fmt.Sprintf("%s    ?", info)
+				case f.dirCount < 1000:
+					info = fmt.Sprintf("%s %4d", info, f.dirCount)
+				default:
+					info = fmt.Sprintf("%s 999+", info)
 				}
-				info = fmt.Sprintf("%s %4s", info, sz)
 				continue
 			}
 
-			switch {
-			case f.dirCount < -1:
-				info = fmt.Sprintf("%s    !", info)
-			case f.dirCount < 0:
-				info = fmt.Sprintf("%s    ?", info)
-			case f.dirCount < 1000:
-				info = fmt.Sprintf("%s %4d", info, f.dirCount)
-			default:
-				info = fmt.Sprintf("%s 999+", info)
+			var sz string
+			if f.IsDir() && f.dirSize < 0 {
+				sz = "-"
+			} else {
+				sz = humanize(f.TotalSize())
 			}
+			info = fmt.Sprintf("%s %4s", info, sz)
 		case "time":
 			info = fmt.Sprintf("%s %*s", info, max(len(gOpts.infotimefmtnew), len(gOpts.infotimefmtold)), infotimefmt(f.ModTime()))
 		case "atime":
@@ -474,7 +474,7 @@ func (win *win) printDir(ui *ui, dir *dir, context *dirContext, dirStyle *dirSty
 			filename = append(filename, []rune(gOpts.truncatechar)...)
 			filename = append(filename, lastPart...)
 		}
-		for i := runeSliceWidth(filename); i < maxFilenameWidth; i++ {
+		for j := runeSliceWidth(filename); j < maxFilenameWidth; j++ {
 			filename = append(filename, ' ')
 		}
 		s = append(s, filename...)
@@ -785,11 +785,11 @@ func (ui *ui) drawPromptLine(nav *nav) {
 
 	var prompt string
 
-	prompt = strings.Replace(gOpts.promptfmt, "%u", gUser.Username, -1)
-	prompt = strings.Replace(prompt, "%h", gHostname, -1)
-	prompt = strings.Replace(prompt, "%f", fname, -1)
+	prompt = strings.ReplaceAll(gOpts.promptfmt, "%u", gUser.Username)
+	prompt = strings.ReplaceAll(prompt, "%h", gHostname)
+	prompt = strings.ReplaceAll(prompt, "%f", fname)
 
-	if printLength(strings.Replace(strings.Replace(prompt, "%w", pwd, -1), "%d", pwd, -1)) > ui.promptWin.w {
+	if printLength(strings.ReplaceAll(strings.ReplaceAll(prompt, "%w", pwd), "%d", pwd)) > ui.promptWin.w {
 		names := strings.Split(pwd, sep)
 		for i := range names {
 			if names[i] == "" {
@@ -797,23 +797,23 @@ func (ui *ui) drawPromptLine(nav *nav) {
 			}
 			r, _ := utf8.DecodeRuneInString(names[i])
 			names[i] = string(r)
-			if printLength(strings.Replace(strings.Replace(prompt, "%w", strings.Join(names, sep), -1), "%d", strings.Join(names, sep), -1)) <= ui.promptWin.w {
+			if printLength(strings.ReplaceAll(strings.ReplaceAll(prompt, "%w", strings.Join(names, sep)), "%d", strings.Join(names, sep))) <= ui.promptWin.w {
 				break
 			}
 		}
 		pwd = strings.Join(names, sep)
 	}
 
-	prompt = strings.Replace(prompt, "%w", pwd, -1)
+	prompt = strings.ReplaceAll(prompt, "%w", pwd)
 	if !strings.HasSuffix(pwd, sep) {
 		pwd += sep
 	}
-	prompt = strings.Replace(prompt, "%d", pwd, -1)
+	prompt = strings.ReplaceAll(prompt, "%d", pwd)
 
 	if len(dir.filter) != 0 {
-		prompt = strings.Replace(prompt, "%F", fmt.Sprint(dir.filter), -1)
+		prompt = strings.ReplaceAll(prompt, "%F", fmt.Sprint(dir.filter))
 	} else {
-		prompt = strings.Replace(prompt, "%F", "", -1)
+		prompt = strings.ReplaceAll(prompt, "%F", "")
 	}
 
 	// spacer
@@ -821,7 +821,7 @@ func (ui *ui) drawPromptLine(nav *nav) {
 	if avail > 0 {
 		prompt = strings.Replace(prompt, "%S", strings.Repeat(" ", avail), 1)
 	}
-	prompt = strings.Replace(prompt, "%S", "", -1)
+	prompt = strings.ReplaceAll(prompt, "%S", "")
 
 	ui.promptWin.print(ui.screen, 0, 0, st, prompt)
 }
@@ -1116,7 +1116,6 @@ func (ui *ui) draw(nav *nav) {
 		ui.sxScreen.lastFile = ui.regPrev.path
 		ui.sxScreen.showSixels()
 	}
-
 }
 
 func findBinds(keys map[string]expr, prefix string) (binds map[string]expr, ok bool) {