Fix issue with defaulting to reading from file while providing other args

main.go

@@ -26,7 +26,7 @@ var programName = os.Args[0]
 
 func main() {
 	recurse := flag.String("r", "", "recurse into directories")
-	file := flag.String("f", "sync", "file to read instructions from")
+	file := flag.String("f", "", "file to read instructions from")
 	debug := flag.Bool("d", false, "debug")
 	flag.Parse()
 
@@ -43,19 +43,40 @@ func main() {
 		log.SetFlags(log.Lmicroseconds)
 	}
 
-	log.Printf("Recurse: %s", *recurse)
-	log.Printf("File: %s", *file)
-
 	instructions := make(chan *LinkInstruction, 1000)
 	status := make(chan error)
-	if *recurse != "" {
+
+	// Check input sources in priority order
+	switch {
+	case *recurse != "":
+		log.Printf("Recurse: %s", *recurse)
 		go ReadFromFilesRecursively(*recurse, instructions, status)
-	} else if *file != "" {
+	
+	case *file != "":
+		log.Printf("File: %s", *file)
 		go ReadFromFile(*file, instructions, status, true)
-	} else if len(os.Args) > 1 {
+	
+	case len(flag.Args()) > 0:
+		log.Printf("Reading from command line arguments")
 		go ReadFromArgs(instructions, status)
-	} else {
+	
+	case IsPipeInput():
+		log.Printf("Reading from stdin pipe")
 		go ReadFromStdin(instructions, status)
+	
+	default:
+		if _, err := os.Stat("sync"); err == nil {
+			log.Printf("Using default sync file")
+			go ReadFromFile("sync", instructions, status, true)
+		} else {
+			log.Printf("No input provided")
+			log.Printf("Provide input as: ")
+			log.Printf("Arguments - %s <source>,<target>,<force?>", programName)
+			log.Printf("File - %s -f <file>", programName)
+			log.Printf("Folder (finding sync files in folder recursively) - %s -r <folder>", programName)
+			log.Printf("stdin - (cat <file> | %s)", programName)
+			os.Exit(1)
+		}
 	}
 
 	go func() {
@@ -92,16 +113,19 @@ func main() {
 	wg.Wait()
 	log.Println("All done")
 	if instructionsDone == 0 {
-		log.Printf("No input provided")
+		log.Printf("No instructions were processed")
-		log.Printf("Provide input as: ")
-		log.Printf("Arguments - %s <source>,<target>,<force?>", programName)
-		log.Printf("File - %s -f <file>", programName)
-		log.Printf("Folder (finding sync files in folder recursively) - %s -r <folder>", programName)
-		log.Printf("stdin - (cat <file> | %s)", programName)
 		os.Exit(1)
 	}
 }
 
+func IsPipeInput() bool {
+	info, err := os.Stdin.Stat()
+	if err != nil {
+		return false
+	}
+	return info.Mode()&os.ModeNamedPipe != 0
+}
+
 func ReadFromFilesRecursively(input string, output chan *LinkInstruction, status chan error) {
 	defer close(output)
 	defer close(status)
@@ -158,6 +182,7 @@ func ReadFromFilesRecursively(input string, output chan *LinkInstruction, status
 	}
 	wg.Wait()
 }
+
 func ReadFromFile(input string, output chan *LinkInstruction, status chan error, doclose bool) {
 	if doclose {
 		defer close(output)
@@ -185,6 +210,7 @@ func ReadFromFile(input string, output chan *LinkInstruction, status chan error,
 		output <- &instruction
 	}
 }
+
 func ReadFromArgs(output chan *LinkInstruction, status chan error) {
 	defer close(output)
 	defer close(status)
@@ -200,6 +226,7 @@ func ReadFromArgs(output chan *LinkInstruction, status chan error) {
 		output <- &instruction
 	}
 }
+
 func ReadFromStdin(output chan *LinkInstruction, status chan error) {
 	defer close(output)
 	defer close(status)
@@ -207,27 +234,19 @@ func ReadFromStdin(output chan *LinkInstruction, status chan error) {
 	workdir, _ := os.Getwd()
 	log.Printf("Reading input from stdin")
 
-	info, err := os.Stdin.Stat()
+	scanner := bufio.NewScanner(os.Stdin)
-	if err != nil {
+	for scanner.Scan() {
-		log.Fatalf("Failed to stat stdin: %s%+v%s", ErrorColor, err, DefaultColor)
+		line := scanner.Text()
+		instruction, err := ParseInstruction(line, workdir)
+		if err != nil {
+			log.Printf("Error parsing line: %s'%s'%s, error: %s%+v%s", SourceColor, line, DefaultColor, ErrorColor, err, DefaultColor)
+			continue
+		}
+		output <- &instruction
+	}
+	if err := scanner.Err(); err != nil {
+		log.Fatalf("Error reading from stdin: %s%+v%s", ErrorColor, err, DefaultColor)
 		status <- err
 		return
 	}
-	if info.Mode()&os.ModeNamedPipe != 0 {
-		scanner := bufio.NewScanner(os.Stdin)
-		for scanner.Scan() {
-			line := scanner.Text()
-			instruction, err := ParseInstruction(line, workdir)
-			if err != nil {
-				log.Printf("Error parsing line: %s'%s'%s, error: %s%+v%s", SourceColor, line, DefaultColor, ErrorColor, err, DefaultColor)
-				continue
-			}
-			output <- &instruction
-		}
-		if err := scanner.Err(); err != nil {
-			log.Fatalf("Error reading from stdin: %s%+v%s", ErrorColor, err, DefaultColor)
-			status <- err
-			return
-		}
-	}
 }