How can I open an app using Terminal? I want to be able to open any given app from the terminal, now I have tried

osascript -e 'open app "Calendar"'

I have tried for Mail, Calendar and Slack.. Slack acctually opens but it does generate a error msg in terminal.. The two others generates errors and doesn't open. The errors are Execution errors.

Now I tried with AppleScript, is bash better?

How can this be done?
You can use open’s -a option:

open -a Mail


You can specify the application path instead:

open /Applications/Mail.app


If you want to use AppleScript (osascript from command line), open app isn't quite equivalent. Instead, you can either use

osascript -e 'tell application "Mail" to activate'


or

osascript -e 'tell application "Mail" to launch'


You can see this question for the difference between the two.