how do i open a .command file that i have in downloads?

its a shell script. the terminal pops up because it is runinng, but you can open terminal first and do a "cd ~/downloads" (or whatever directory you downloaded it to) and then run the command with "./nameofyourfile.command"

If you trust your professor. What is the script supposed to do? You can open it with a text editor and verify what commands he put in the script. Sudo will run the script as superuser (root access). If you don't know what the commands in the script do, do the second suggestion I posted in the previous reply: "chmod 777 yourfile.command" followed by "./yourfile.command". This will give your user account, your group, and other users access to read, write and execute the file. If there are commands in script that try to access directories or files that you do not have access to, they will fail.

What kind of class is this? Most shell scripts end in .sh, so this seems to be something specifically created for Mac OSX users. If you are in a computer/IT-related degree program, you should probably learn what the shell commands do anyway.

run it as superuser then: "sudo ./yourfile.command"

if that doesn't work then: "chmod 777 yourfile.command" followed by "./yourfile.command"