英文：
/bin: where binary programs live.
/boot: the special programs that start the system when you turn the machine on.
/dev: aaaaaalll the "device" listings for hardware of every concievable flavor, along with some "imaginary" devices,
lile /dev/null and /dev/zero. When you get a random number it usually comes from /dev/random.
/etc: configuration files.
/home: the user's directories live here.
/lib: the library files that programs need to run, if they are compiled to link against these libraries.
/lost+found: look here after a system crash/kernel panic or other extreme scenario to find "orphaned" files.
/misc: kinda reminds you of /etc, doesn't it? Every time I see this folder on a system, it's empty, but I ascertain that
it stands for "miscellaneous", and I think it may be a place for users to keep their own "/etc" type files?
/mnt: "mount", the directory that acts as a gateway to every other disk or file system. Floppies are accessed from
/mnt/floppy, your second hard drive might be /mnt/hd here, and so on.
/opt: "optional", where programs that are installed after the initial system install sometimes end up.
/proc: running "processes". The "everything is a file" paradigm carried to the Linux degree!
This folder hosts files
which keep tabs on boring stuff like what daemons are running and the process ID of Emacs while you have
Emacs open.
/root: root's home!
/sbin: the "system-administrator's bin file", which hosts programs that would be in /bin if they didn't have "root-only"
access permissions.
/tmp: "temporary" files, of use by programs which need to throw together a data file on-the-fly in preperation for
executing some other task. This folder gets flushed on reboot.
/usr: "user". Practically a whole other system in here, /usr/bin is still more binaries, /usr/doc and /usr/share/doc are
documentation folders, /usr/share/games/fortune is where the funny quotes come from when you log on (if
that feature is enabled). The idea is that this should be where files/programs accessible by all users should
be, and thus your desktop backgrounds come from /usr/share/wallpapers, or such. The other case is newly
installed programs sometimes end up in /usr/local/bin.
/var: "variable". System logs in here, recording such things as the last foo commands typed at the prompt, start-up
boot messages, and such.
中文的:
/bin 二进制可执行命令 binary
/dev 设备特殊文件 device
/etc 系统管理和配置文件 1,editable text configuration 2,etcetera
/etc/rc.d 启动的配置文件和脚本 run commands
/home 用户主目录的基点，
/lib 标准程序设计库，又叫动态链接共享库 library
/sbin 系统管理命令，这里存放的是系统管理员使用的管理程序 system binary
/tmp 共用的临时文件存储点 temporary
/root 系统管理员的主目录
/mnt 系统提供这个目录是让用户临时挂载其他的文件系统 mount
/lost+found 这个目录平时是空的，系统非正常关机而留下“无家可归“的文件就在这里
/proc 虚拟的目录，是系统内存的映射。可直接访问这个目录来获取系统信息 processes
/var 某些大文件的溢出区，比方说各种服务的日志文件 variable
/usr 最庞大的目录，要用到的应用程序和文件几乎都在这个目录。其中包括：1,user 2, Unix System Resources
/usr/bin 众多的应用程序
/usr/sbin 超级用户的一些管理程序
/usr/include Linux下开发和编译应用程序所需要的头文件
/usr/lib 常用的动态链接库和软件包的配置文件
/usr/src 源代码，linux内核的源代码就放在这里
/usr/local/bin 本地增加的命令
/usr/local/lib 本地增加的库
其中有的文件夹的解释有多种,以后如果能找到原始的权威的解释就好了.