# 使用grep找到在一个文件但是不在另一个文件中的记录

Say we have a file a, which has the following contentL:

and b,

What if we want to get all those in file a and not in file b, in this case, a, b, e?

To qutoe from the page

The above command is doing the following things:

So remember the order of file a and b matters if you really understand what the command is doing.