MacOS – How to input ctrl+` (grave accent)

The standard U.S. layout has a few dead key states under ⌥:

` isn't a dead key in U.S. Extended:

If you want to leave the left ⌥ free for other functions, you can create a custom .keylayout with Ukelele.

Keyboard Maestro

You can do this with Keyboard Maestro, using a macro such as this:

Alfred

You can set up a custom hotkey to launch an app using a workflow:

Go to the workflows tab, create a new workflow and add a hotkey and a 'launch apps' with Terminal selected as the app to launch.

KeyRemap4MacBook

You can use KeyRemap4MacBook with a private.xml such as this:

<?xml version="1.0"?>
<root>
  <vkopenurldef>
    <name>KeyCode::VK_OPEN_URL_Terminal</name>
    <url>file:///Applications/Utilities/Terminal.app</url>
  </vkopenurldef>
  <item>
    <name>Activate Terminal with ⌘Space</name>
    <identifier>ActivateTerminalWithCmdSpace</identifier>
    <autogen>
      __KeyToKey__
      KeyCode::SPACE, VK_COMMAND | ModifierFlag::NONE,
      KeyCode::VK_OPEN_URL_Terminal
    </autogen>
  </item>
</root>

Automator Service

You can create a service in Automator:

…then in System Preferences → Keyboard → Shortcuts → Services you can assign a keyboard command to run it.