I have lost the prompt on Terminal on my Mac; unable to get commands to work
Your command is still running. Type Ctrl-Z to get your prompt back, followed by bg and Enter to let Minecraft continue in the background. 

If you want to avoid similar issues in the future, call either the shell script itself or at least java with &amp; at the end to put it into the background directly:

java -Xmx1024M -Xms1024M -jar craftbukkit.jar &amp;