假设顺序并不重要，

grep -F -f FILE2 FILE1

应该做的伎俩。 （这工作，因为一个鲜为人知的事实：在 -F 选项的grep 并不仅仅意味着比赛这种固定字符串，它意味着匹配任何这些换行符分隔固定字符串。）

should do the trick. (This works because of a little-known fact: the -F option to grep doesn't just mean "match this fixed string," it means "match any of these newline-separated fixed strings.")