In this lesson, I will introduce your first three commands: PWD (print working directory), CD (change directory), and ls (list files and directories).

在这一节，我会首先向你介绍三个命令：pwd(打印当前工作目录)，cd(改变目录)，还有ls(显示出文件和目录)。

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The notebook's external storage options include a LS-120 SuperDisk drive (which also supports 3.5-inch floppy disks), a CD-ROM drive, a DVD ROM drive and hard disk drive options of up to 20G bytes.

CNN: Panasonic introduces 'tough' notebook PC