1、 打开终端 直接输入 open /Applications/xxx（应用的名称）.app 比如打开iTunes输入：open /Applications/iTunes.app （注意open之后需要空格再输入斜杠 / ）
2、Mac 下在终端中打开应用程序的命令
from:http://macosx.com/forums/howto-faqs/29520-how-launch-application-terminal.html
The command is simply open (which can also be used for opening directories). The most basic example of launching an application:
open /path/to/some.app
More complex possibilities also exist:wxruiao.com
open "/Volumes/Macintosh HD/foo.txt"
opens the document in the default application for its type (as determined by LaunchServices).
open /Applications/
opens that directory in the Finder.
open -a /Applications/TextEdit.app "/Volumes/Macintosh HD/foo.txt"
opens the document in the application specified (in this case, TextEdit).
open -e "/Volumes/Macintosh HD/foo.txt"
opens the document in TextEdit (the -e option specifies TextEdit).
open http://www.apple.com/
opens the URL in the default browser (lynx, naturally *wink*)
open "file://localhost/Volumes/Macintosh HD/foo.txt"
opens the document in the default application for its type (as determined by LaunchServices).
open "file://localhost/Volumes/Macintosh HD/Applications/"
opens that directory in the Finder.