Odds are you will never run this identical command.

很可能你永远不会执行这个相同的命令。

If I just ran this command without this, I could not do anything.

如果我只是在没有这个的情况下运行这个命令，我将无法执行任何操作。

So when I run this command after hitting Enter, nothing again seems to happen.

所以当我在按Enter之后运行这个命令时，似乎什么也没有发生。

Then, in the next line we're running the grep command which is just search for a substring in some file and we're searching for the string foobar in the file.

然后，在下一行中，我们运行 grep 命令，该命令只是在某个文件中搜索子字符串，并且我们在文件中搜索字符串 foobar 。