Shell scripts are text files with commands to be interpreted by a particular shell. However, the Bourne shell has more flexibility in terms of file names, etc, and is smaller. Each user starts with a quota of 15 megabytes of disk space.
More space is purchased with pizza or sushi.
No, really, see the systems adminstrator and whine. System news is a means of disseminating information to all users. This is normally run automatically when you log on, and you may run it manually at any time you are online. In general, you don't. But if you think you have something that should go there, discuss it with the systems administrator.