Opening a new terminal from the command line and running a command on Mac OS X?

osascript -e 'tell app "Terminal"
    do script "echo hello"
end tell'

This opens a new terminal and executes the command "echo hello" inside it.

This works, at least under Mountain Lion. It does initialize an interactive shell each time, although you can replace that after-the-fact by invoking it as "macterm exec your-command". Store this in bin/macterm in your home directory and chmod a+x bin/macterm:

#!/usr/bin/osascript

on run argv
   tell app "Terminal" 
   set AppleScript's text item delimiters to " "
        do script argv as string
        end tell   
end run 

You can do it in a roundabout way:

% cat /tmp/hello.command
#! /bin/sh -
say hello
% chmod +x /tmp/hello.command
% open /tmp/hello.command

Shell scripts which have the extension .command and which are executable, can be double-clicked on to run inside a new Terminal window. The command open, as you probably know, is equivalent to double-clicking on a Finder object, so this procedure ends up running the commands in the script within a new Terminal window.

Slightly twisted, but it does appear to work. I feel sure there must be a more direct route to this (what is it you're actually trying to do?), but it escapes me right now.