Article in English: By default, this is in the Utilities folder, located in the Applications folder. If a normal Force Quit doesn't work, you may need to use this method to end the program. The “top” command displays information about the applications that are currently running. Under the column titled "COMMAND", find the name of the application you wish to quit. The COMMAND list may use a truncated name for the program. Look for a name that looks similar to the program you are trying to close. Once you find the name of program, find the number to the immediate left of it, under the PID column. Make a note of the PID number. This will exit the list of applications and return you to the command line. Replace the "###" with the number from the PID Column you just located. For example: If you were trying to quit iTunes, and found iTunes to have PID number 3703, you would type "kill 3703". If the program does not respond to the “kill” command, type “sudo kill -9 ###”, replacing ### with the PID number. The application should quit and you can be relaunched.

Summary in Vietnamese:
Mở tiện ích Terminal. Gõ "top" và nhấn ⏎ Return. Tìm chương trình mà bạn muốn đóng. Tìm số PID (Process ID - mã số nhận diện tiến trình muốn dừng). Gõ "q". Nhập "kill ###". Thoát Terminal.