Respect NO_COLOR environmental variable

src/app.go

@@ -69,7 +69,7 @@ func checkForUpdates(app *cli.App) {
 			app.Name,
 		)
 	} else {
-		fmt.Printf("%s: %s at %s\n", green.Sprint("Update available"), version, resp.Request.URL.String())
+		fmt.Printf("%s: %s at %s\n", printColor("green", "Update available"), version, resp.Request.URL.String())
 	}
 }
 
@@ -85,7 +85,7 @@ func GetApp() *cli.App {
 		},
 		Usage:                "F2 is a command-line tool for batch renaming multiple files and directories quickly and safely",
 		UsageText:            "FLAGS [OPTIONS] [PATHS...]",
-		Version:              "v1.5.6",
+		Version:              "v1.5.7",
 		EnableBashCompletion: true,
 		Flags: []cli.Flag{
 			&cli.StringFlag{

src/operation.go

@@ -28,8 +28,8 @@ var (
 	)
 
 	errConflictDetected = fmt.Errorf(
-		"Conflict detected! Please resolve before proceeding or append the %s flag to fix conflicts automatically",
-		yellow.Sprint("-F"),
+		"Resolve conflicts before proceeding or use the %s flag to auto fix all conflicts",
+		printColor("yellow", "-F"),
 	)
 )
 
@@ -188,7 +188,7 @@ func (op *Operation) undo(path string) error {
 		if err = os.Remove(path); err != nil {
 			fmt.Printf(
 				"Unable to remove redundant undo file '%s' after successful operation.",
-				yellow.Sprint(path),
+				printColor("yellow", path),
 			)
 		}
 	}
@@ -204,9 +204,9 @@ func (op *Operation) printChanges() {
 		source := filepath.Join(v.BaseDir, v.Source)
 		target := filepath.Join(v.BaseDir, v.Target)
 
-		status := green.Sprint("ok")
+		status := printColor("green", "ok")
 		if source == target {
-			status = yellow.Sprint("unchanged")
+			status = printColor("yellow", "unchanged")
 		}
 		d := []string{source, target, status}
 		data[i] = d
@@ -217,7 +217,7 @@ func (op *Operation) printChanges() {
 
 // rename iterates over all the matches and renames them on the filesystem
 // directories are auto-created if necessary.
-// Errors are aggregated instead of being reported one by one
+// Errors are aggregated ins""tead of being reported one by one
 func (op *Operation) rename() {
 	var errs []renameError
 
@@ -269,7 +269,7 @@ func (op *Operation) reportErrors() {
 	for i, v := range op.matches {
 		source := filepath.Join(v.BaseDir, v.Source)
 		target := filepath.Join(v.BaseDir, v.Target)
-		d := []string{source, target, green.Sprint("success")}
+		d := []string{source, target, printColor("green", "success")}
 		data[i] = d
 	}
 
@@ -284,7 +284,7 @@ func (op *Operation) reportErrors() {
 		d := []string{
 			source,
 			target,
-			red.Sprintf("%s", strings.TrimPrefix(msg, ": ")),
+			printColor("red", strings.TrimPrefix(msg, ": ")),
 		}
 		data[i+len(op.matches)] = d
 	}
@@ -316,7 +316,7 @@ func (op *Operation) handleErrors() error {
 	if err == nil && len(op.matches) > 0 {
 		return fmt.Errorf(
 			"Some files could not be renamed. To revert the changes, run %s",
-			yellow.Sprint("f2 -u"),
+			printColor("yellow", "f2 -u"),
 		)
 	} else if err != nil && len(op.matches) > 0 {
 		return fmt.Errorf("The above files could not be renamed")
@@ -392,7 +392,7 @@ func (op *Operation) apply() error {
 	op.printChanges()
 	fmt.Printf(
 		"Append the %s flag to apply the above changes\n",
-		yellow.Sprint("-x"),
+		printColor("yellow", "-x"),
 	)
 
 	return nil

src/utils.go

@@ -11,6 +11,23 @@ import (
 	"github.com/olekukonko/tablewriter"
 )
 
+func printColor(color, text string) string {
+	if _, ok := os.LookupEnv("NO_COLOR"); ok {
+		return text
+	}
+
+	switch color {
+	case "yellow":
+		return yellow.Sprint(text)
+	case "green":
+		return green.Sprint(text)
+	case "red":
+		return red.Sprint(text)
+	}
+
+	return text
+}
+
 func printError(silent bool, err error) {
 	if !silent {
 		fmt.Fprintln(os.Stderr, err)

src/validation.go

@@ -97,7 +97,7 @@ func (op *Operation) reportConflicts() {
 			slice := []string{
 				strings.Join(v.source, ""),
 				"",
-				red.Sprint("❌ [Empty filename]"),
+				printColor("red", "❌ [Empty filename]"),
 			}
 			data = append(data, slice)
 		}
@@ -108,7 +108,7 @@ func (op *Operation) reportConflicts() {
 			slice := []string{
 				strings.Join(v.source, ""),
 				v.target,
-				red.Sprint("❌ [Path already exists]"),
+				printColor("red", "❌ [Path already exists]"),
 			}
 			data = append(data, slice)
 		}
@@ -120,7 +120,7 @@ func (op *Operation) reportConflicts() {
 				slice := []string{
 					s,
 					v.target,
-					red.Sprint("❌ [Overwriting newly renamed path]"),
+					printColor("red", "❌ [Overwriting newly renamed path]"),
 				}
 				data = append(data, slice)
 			}
@@ -133,9 +133,11 @@ func (op *Operation) reportConflicts() {
 				slice := []string{
 					s,
 					v.target,
-					red.Sprintf(
-						"❌ [Invalid characters present: (%s)]",
-						v.cause,
+					printColor("red",
+						fmt.Sprintf(
+							"❌ [Invalid characters present: (%s)]",
+							v.cause,
+						),
 					),
 				}
 				data = append(data, slice)
@@ -149,9 +151,11 @@ func (op *Operation) reportConflicts() {
 				slice := []string{
 					s,
 					v.target,
-					red.Sprintf(
-						"❌ [Maximum file name exceeded: (%s)]",
-						v.cause,
+					printColor("red",
+						fmt.Sprintf(
+							"❌ [Maximum file name exceeded: (%s)]",
+							v.cause,
+						),
 					),
 				}
 				data = append(data, slice)