simplify readme and make a force flag for local overrides

internal/config/config.go

@@ -56,6 +56,7 @@ type Config struct {
 	InputPath   string
 	OutputPath  string
 	AppendMode  bool
+	Force       bool
 	SingleFile  bool
 	MaxSize     int64
 	MaxDepth    int
@@ -79,6 +80,7 @@ func Parse() (*Config, error) {
 		input       string
 		output      string
 		appendMd    bool
+		force       bool
 		maxSize     int64
 		maxDepth    int
 		ignores     stringSlice
@@ -91,6 +93,7 @@ func Parse() (*Config, error) {
 	flag.StringVar(&input, "i", "", "single file input (append mode only)")
 	flag.StringVar(&output, "o", "", "output markdown file path (required)")
 	flag.BoolVar(&appendMd, "a", false, "append to existing output file")
+	flag.BoolVar(&force, "f", false, "overwrite existing output file (non-append mode)")
 	flag.Int64Var(&maxSize, "max-size", DefaultMaxSize, "max file size in bytes")
 	flag.IntVar(&maxDepth, "max-depth", DefaultMaxDepth, "max directory recursion depth")
 	flag.Var(&ignores, "ignore", "additional ignore patterns (glob, repeatable)")
@@ -118,6 +121,7 @@ func Parse() (*Config, error) {
 	cfg := &Config{
 		OutputPath:  output,
 		AppendMode:  appendMd,
+		Force:       force,
 		MaxSize:     maxSize,
 		MaxDepth:    maxDepth,
 		Ignores:     append(DefaultIgnores, ignores...),
@@ -147,8 +151,8 @@ func Parse() (*Config, error) {
 	cfg.AbsRoot = abs
 
 	if !appendMd {
-		if _, err := os.Stat(output); err == nil {
-			return nil, fmt.Errorf("output file %s already exists (use -a to append)", output)
+		if _, err := os.Stat(output); err == nil && !force {
+			return nil, fmt.Errorf("output file %s already exists (use -f to overwrite or -a to append)", output)
 		}
 	}