This is the text of the Commencement address by Steve Jobs, CEO of Apple Computer and of Pixar Animation Studios, delivered on June 12, 2005.

I am honored to be with you today at your commencement from one of the finest universities in the world. I never graduated from college. Truth be told, this is the closest I've ever gotten to a college graduation. Today I want to tell you three stories from my life. That's it. No big deal. Just three stories.

df命令用来查看Linux文件系统相关的信息，如文件系统类型、空间使用情况（大小、已用、可用）及挂载位置等信息。

1、打开terminal ，执行命令 df -Th，执行效果参看本文的配图。

-T：输出文件系统的类型。

-h：以人类可读的格式输出 sizes。

另外：

-a：include dummy file systems。

-t：只显示 选定 文件系统类型的相关信息。

-x：只显示 不是选定 文件系统类型的相关信息。

2、在terminal中依次执行下列命令。

df -t ext4 -hT ：显示文件系统类型 是ext4 的磁盘信息。

df -x tmpfs -hT：显示文件系统类型 不是tmpfs 的磁盘信息。

df -Th /home：显示 /home 所在的磁盘信息。