num=0 while read line || [ -n "${line}" ] do
num=num + 1] done < nowcoder.txt
while read line || [ -n "num -le 5 ] && [ line fi num=num - 1]
done < nowcoder.txt
num=0 while read line || [ -n "${line}" ] do
num=[num + 1] done < nowcoder.txt
while read line || [ -n "line"]doif[num -le 5 ] && [ num−ge0]thenecholine fi num=[num - 1]
done < nowcoder.txt