Ubuntu

1. Hold super key to navigate things;
2. C-o: open file;
3. C-A-F1~F6: open tty1~tty6; C-A-F7: open X;
4. export PATH=${PATH}:/home/wade/bin set path variable.
5. Alt+HOME: open home folder; Ctrl + N: open new folder.
6. in folder:  select a file and Alt+ENTER to see property
   
7. Alt+Ctrl+t : open terminal
8. dict command to look up a word. dict banana.
9. How to install .bin file on ubuntu:
   1. $ chmod a+x name_of_file.bin
   2. $ sudo ./name_of_file.bin
10. How to install Adobe Reader on ubunto:
    1. if you have a 64bit system, do not forget to install also this package libxml2:i386
       
    2. $ sudo apt-get install libxml2:i386
    3. Otherwise, acroread will fail
11. 在Emacs中用ibus输入法切换输入法问题:

    sudo add-apt-repository ppa:irie/elisp 
    sudo apt-get update
    sudo apt-get install ibus-el 
    安装完成之后在~/.emacs添加下面两行
    (require 'ibus)      
      (add-hook 'after-init-hook 'ibus-mode-on)
    最后在ibus中设置输入法切换快捷键Ctrl-Space改为Shift-Space.
    (把ibus里的关闭输入法设置为Ctrl-Space) 
    因为在emacs中，Ctrl-Space为设置Mark的功能

12. How to install sublime text 2:

    sudo add-apt-repository ppa:webupd8team/sublime-text-2
    sudo apt-get update
    sudo apt-get install sublime-text
    PPA: personal package archive. this is the way to add a ppa.

13. System monitor: $ gnome-system-monitor
14. Remove a ppa:enter /etc/apt/sources.list.d/ and choose what you want to remove.
15. killall -9 <pro_name>: force kill process <pro_name>: http://codingstandards.iteye.com/blog/986313 
16. w: print current system condition information; w - show who is logged on and what they are doing, displays information about the users currently on the machine, and their processes.
17. tty - print the file name of the terminal connected to standard input 
18. how to install office2010 on ubuntu(install PlayOnLinux): http://www.tutonics.com/2012/12/easily-install-microsoft-office-in.html#.UYltSqD_6b4
19. linux下安装qq：http://www.longene.org/forum/viewtopic.php?f=6&t=4700
    
20. Change back to default login screen:

    $ sudo update-alternatives --config default.plymouth
    $ sudo update-initramfs -u
    $ sudo dpkg-reconfigure lightdm

21. f
    
22. ff