oakland/Learn-Linux-In-5-Ddays.txt

## Learn-Linux-In-5-Ddays.txt
1. An operating system is a collection of software that manages hardware resources and provides an environment where applications run.
2. Linux Kernel + Apps = Distro
3. Linux Kernel is the layer that sits between the hardware and applications. Said in another way that it's the intermediary between software and hardware.
4. The most popular linux operating distributions are Red Hat Enterprise Linux and Ubuntu. CentOS is a RedHat Enterprise Linux derivitive that completely free.
5. PuTTY is a windows SSH client.
6. The command line utility ssh is used in Mac.
7. pwd - Displays the present working directory. cat - Concatenates and displays files. echo - Displays arguments to the screen. man - Displays the online manual. exit - Exits the shell or your current session. clear - Clears the screen.
8. Pointer 有点像快捷方式，比如一个文件夹的桌面快捷方式就是一个 pointer ，而这个 pointer 指向的是真正的文件夹的内容，有时候改变 pointer 和改变文件夹内容是两件事情。Pointer 还可以类必成 url 和真是的网页内容。
	1. An operating system is a collection of software that manages hardware resources and provides an environment where applications run.
	2. Linux Kernel + Apps = Distro
	3. Linux Kernel is the layer that sits between the hardware and applications. Said in another way that it's the intermediary between software and hardware.
	4. The most popular linux operating distributions are Red Hat Enterprise Linux and Ubuntu. CentOS is a RedHat Enterprise Linux derivitive that completely free.
	5. PuTTY is a windows SSH client.
	6. The command line utility ssh is used in Mac.
	7. pwd - Displays the present working directory. cat - Concatenates and displays files. echo - Displays arguments to the screen. man - Displays the online manual. exit - Exits the shell or your current session. clear - Clears the screen.
	8. Pointer 有点像快捷方式，比如一个文件夹的桌面快捷方式就是一个 pointer ，而这个 pointer 指向的是真正的文件夹的内容，有时候改变 pointer 和改变文件夹内容是两件事情。Pointer 还可以类必成 url 和真是的网页内容。