package main import ( "bufio" "fmt" "os" "strconv" "strings" ) func main() { if len(os.Args) < 2 { fmt.Fprintf(os.Stderr, "usage: %s \n", os.Args[0]) os.Exit(1) } fieldNum, err := strconv.Atoi(os.Args[1]) if err != nil || fieldNum < 1 { fmt.Fprintln(os.Stderr, "error: invalid field number") os.Exit(1) } scanner := bufio.NewScanner(os.Stdin) for scanner.Scan() { line := scanner.Text() fields := strings.Fields(line) if len(fields) >= fieldNum { fmt.Println(fields[fieldNum-1]) } } if err := scanner.Err(); err != nil { fmt.Fprintln(os.Stderr, "error reading input:", err) } }