如何在bash中杀死进程？

Question

我使用了以下bash代码：

for pid in `top -n 1 | awk '{if($8 == "R") print $1;}'`
do
  kill $pid
done

它说：

./kill.sh: line 3: kill: 29162: arguments must be process or job IDs
./kill.sh: line 3: kill: 29165: arguments must be process or job IDs
./kill.sh: line 3: kill: 29166: arguments must be process or job IDs
./kill.sh: line 3: kill: 29169: arguments must be process or job IDs

有什么想法吗？谢谢！