查询出每门课都大于80分的学生姓名 select distinct name from aa where name not in (select distinct name from aa where fengshu<=80) cut命令可用来提取文件中某一列或某些列， 列的定义可以通过字节(bytes, -b)数，字符(character, -c)数，或者字段（field, -f）数