Alias: An assumed identity. No, really. It's a user- or system-defined name for a command. See the 'alias' entry for details. There are a number of default aliases defined by the system.

Argument: Anything that follows a command. These are typically options and parameters to pass to a command, as well as filenames.

Background / foreground: Jobs run in the foreground tie up the window you are working in. Sometimes, this is inevitable, such as when the program requires user interaction. However, jobs that run in batch mode can be run in the background, so that the window remains free for other things. Be careful of running jobs in the background that send output to the screen. You may be in for some nasty surprises. In such cases, it is best to redirect the output to a file.

Bang: A cute name for the exclamation mark (!). Those crazy CS guys...

Console window: This is normally the window that controls the window manager. Sometimes, I also refer to any window as a console. Most of the time, I refer to a physical machine as a console.

Control characters: These characters do not show up on the screen and are entered by holding down the CONTROL key and hitting another key. These characters do count as real characters in some situations, and can be hard to isolate, so take care with them in files, filenames, and such.

Dot files: Hidden files in your home directory that define a lot of the defaults for your account, including the window layout when you login, custom aliases, and many other features.

File permission: Determines who has permission to read, write, and execute a file. You can see each file's permission with the dir command. See the chmod listing for a more detailed description of file permissions.

Home directory: Where your account is. It is abbreviated as ~/. It is also where you normally start when you log in.

Host: A computer. The host name should be part of the prompt. Each host also has an ID number, which you can see with 'hostid'. Cool, huh?

Job / process: A program that is running is referred to as a job or a process. The only difference is that there is a job number (seen with jobs) and a process number (seen with ps) for each operation.

Login session: Everything between when you log in and when you log out. You can actually have several login sessions at the same time. In fact, each window is a separate login session.

Man page: The easiest place to get information about commands, although it can difficult to figure out what they mean sometimes. As if this file was really much better... Access man pages with the man command.

PID: Process id number, found for a process with the ps command.

Redirect: Using < or > to specify input or output from somewhere other than the standard locations.

Root directory: The source of all this evil that is the network. It's the bottom level directory of the system and is denoted by /.

Root user: The super-user. The one who can do anything. The madman who can destroy all your hard work with a single keystroke. But they wouldn't do anything like that. No, no, of course not, it takes at least six keystrokes...

Script (shell script): A collection of commands in a file. It's a way to run many commands in a batch mode. There are many things that you can do with scripts.If you are interested in writing a shell script to do something and need help, please contact one of the system administrators, or check a UNIX reference book.

Shell: An interface between you, the user, and the underlying UNIX system. By default, SACL users use the shell, tcsh. This has the features of command completion and command recall as well as some other nice things. Each time you open a window, you start up a new shell.

Solaris vs. SunOS: A big headache for system administrators. Solaris is the new standard operating system for Sun Microsystems. It has quite a few advantages over the older SunOS system, but unfortunately, it is different. As a result, there are some commands that used to work and don't any more and other commands that have been changed. Of course, there are also some new Solaris commands that didn't exist before. At this time, structure and fiber are the only machines running Solaris.

Standard output: This is where most output from commands is sent. By default, the standard output is the screen. To save output sent to the screen, you must redirect it. See the > and | commands. Note that sometimes you may not realize that the output is going to the screen and all of a sudden, there's all sorts of stuff flying across your screen. Just interrupt the job with 'Ctrl-C' and run it again with a redirect.

Standard input: Many commands expect input from standard input. By default, this is the keyboard. In most situations, you will actually want the input to come from another file or another command. In these cases, you need to redirect standard input. See the < and | commands. There will be times when you don't realize that input is expected from the keyboard. The command will be issued and the computer will just sit there with a cursor on a blank line; it is expecting input from you. If you meant to redirect input in, just "Ctrl-C" and try again.

Symbolic links: Bigger than a hot dog, but smaller than a Polish. A link is a shortcut to a file. There are also hard links, but symbolic links are better. Just trust me on this one. Links are used to point to a file or directory from somewhere convenient. See the ln command to learn how to make links.

System administrators: The jokers who try and run this circus. In case of emergency, you can contact them. Of course, there won't be much guarantee that you'll get help. Sysads should have the answers, but mostly, we're more lost than everyone else.

Terminal: A terminal is a virtual screen. Each window you open is actually considered to be a separate terminal. When someone else logs in, they also get a terminal. You can determine what terminal you're on with the tty command. The terminal can be useful with the talk and write commands. The problem is that most people open so many windows, that you have no idea which one is which terminal.

Wildcard symbols: These symbols can take on various values. They are described in the Notation section. The most common wildcards symbols are '*' and '?'.

Window: A window system is usually started when you log in at a console. Multiple windows can be opened, each of which starts a new login session on a new terminal. Window manipulations are described in another document.