They learn the president's speeches line by line.

他们一句一句地学习这位总统的演讲。

It reads data from standard input line by line.

它从标准输入逐行读取数据。

For clarity, we'll break that down line by line once again.

为了清晰起见，我们再次将该清单逐行细化。

A lot is happening here, so I'll try to describe it line by line.

这里出现了多行代码，因此我将试着一行行地描述它。

The grep utility filters input line by line and looks for matches.

grep实用工具逐行过滤输入并寻找匹配。