MacOS – open new tab in iTerm and execute command there

Try this

tell application "Firefox"
    activate
    tell application "System Events"
        keystroke tab
        keystroke (key code 125)
        keystroke (key code 125)
        keystroke (key code 125)        
    end tell
end tell

You might not need to activate Firefox if it's the current active app. Them you just need :

tell application "System Events"
    keystroke tab
    keystroke (key code 125)
    keystroke (key code 125)
    keystroke (key code 125)        
end tell

iTerm 2 is a powerful replacement for Terminal.app and it has support for AppleScript. You can use AppleScript to tell it to run commands in a new tab or window.

For example, let's make a little AppleScript action that's callable. Enter the following in to the AppleScript Editor:

on run argv
    set AppleScript's text item delimiters to {" "}
    tell application "iTerm"
        make new terminal
        tell the current terminal
            activate current session
            launch session "Default Session"
            tell the last session
                write text argv as string
            end tell
        end tell
    end tell
end run

and then save it as a Script in ~/Documents/Scripts/run-in-new-iterm-tab.scpt. We can now call it from the command line like so:

/Users/ian
> osascript ~/Documents/Scripts/run-in-new-iterm-tab.scpt ls ~/Documents/Scripts

/Users/ian
>

and I get a new tab in my iTerm session with:

Last login: Thu Aug 28 22:17:17 on ttys003
ls /Users/ian/Documents/Scripts

/Users/ian
> ls /Users/ian/Documents/Scripts
edit                         keep_drives_alive.sh         run-in-new-iterm-tab.scpt    touch-in-order.pl
find-missing-itunes-files.pl keep_drives_alive.sh~        start-utorrent.scpt          touch-in-order.pl~

/Users/ian
>

Which is not too bad. There are some refinements you can make to the AppleScript like maintaining the current working directory when you call the command. But that's gets you in the ballpark.

If you use this hint in this question you can turn the whole thing in to a bash-wrapped script that's even easier to execute:

#!/usr/bin/env osascript

on run argv
    set AppleScript's text item delimiters to {" "}
    tell application "iTerm"
        make new terminal
        tell the current terminal
            activate current session
            launch session "Default Session"
            tell the last session
                write text argv as string
            end tell
        end tell
    end tell
end run

Save that to a spot on your PATH and make it executable and then you only need to run:

run-in-new-iterm-tab ls ~/Documents/Scripts

to get it to work.