symbol for authentication required denotes that authentication is required.

UNIX Glossary

An IP address is a unique four part number as described in the TCP/IP specifications which identifies a particular networked device (computer, network equipment, printer, etc.) on the internet, e.g. 141.211.144.186. The numeric form of the address always consists of four numbers and is usually written out with those four numbers separated by periods. Every machine connected to the internet has an IP address.

The internet host name is a human readable name associated with an IP address, e.g. www.yahoo.com. The host name is for human benefit since the names are easier to remember than the IP addresses. Networked machines need to convert the host name into a numeric IP address before they can make contact with that machine over the internet.

The host name consists of several words or groups of letters separated by periods. The name generally represents the logical location of the machine within the hierarchy of a given organization, with the dot-separated names becoming more general from left to right.

For example, the internet host name, www.subgroup.biggroup.umich.edu, refers to a specific machine, www which is a one of a group of machines used by the Sub Group Center (subgroup) which is one of many groups in the Big Group (biggroup) which is one of several divisions of the University of Michigan (umich) which is one of many educational institutions (edu).

Those who are familiar which IP naming conventions can usually quickly tell a computer's organizational affiliation by the right two names on the IP name. UNIX users may use the whois command on the right two parts of the name to find the location of more cryptic names, e.g.

    % whois umich.edu
    University of Michigan -- Computing Center (UMICH-DOM)
       535 West William Street
       Ann Arbor, MI 48103

       Domain Name: UMICH.EDU

    (the rest of the output from the whois command is not shown)

UNIX

Paraphrased from "UNIX System Administration Handbook" by Nemeth, Snyder and Seebass:

An elegant, flexible, consistent, powerful, cryptic, idiosyncratic and unstandardized operating system.

UNIX password

The password, known only to you, which must be entered at the Password: prompt when sshing to one of the Sun workstations.

UNIX prompt

The command prompt presented by UNIX where you can type in commands such as ls or pine. It usually looks something like (with your UNIX username subsituted for "jsmith"):

    login1:sofia%

UNIX username

A unique name assigned to a user when a UNIX account is created. The name is usually some combonation of parts the person's proper name or a nickname with a limit of eight characters in length, e.g. johndoe, jsmith, bambi or afabian. The name is generally all lowercase since mixed case is more difficult to type and UNIX is case-sensitive.

The username is public knowledge and easily determinable for any user of the system unlike the UNIX password.

The username is also known as a login or loginname.

X-windows

A windowing system (similar to that of a Macintosh or Microsoft Windows) which provides on easy(?)-to-use graphical interface to the underlying UNIX operating system. In order to use X-windows, the user must be sitting at a UNIX workstation or running an X-server application on their networked personal computer. X-windows applications will not run over text-only types of connections such as telnet or ssh.

current working directory

The directory in the UNIX filesystem that is the default directory for most commands that you execute without a directory specification; i.e. the directory that you are currently in. If you issue commands such as ls without a directory argument, your current working directory is used as the default argument.

You can determing your current working directory entering the pwd command at the UNIX prompt or by displaying the contents of the cwd environment variable with the following UNIX command:

       echo $cwd

Your first current working directory after logging into UNIX is always your home directory.

environment variable

See http://www.sph.umich.edu/computing/unix/concepts.html#environment.

filesystem

The collection of files and directories located on a computer's secondary storage (usually a disk drive or tape). I should be able to say more about this.

home directory

The UNIX directory accessible from all the UNIX workstations that is designated as your own personal workspace. You are automatically placed in this directory when you login into your account. You can return to this directory at any time by entering the command, cd.

You may create whatever files and subdirectories you wish within your home directory. Other users may or may not be able to access files in your home directory depending upon how the file and directory permissions are set. You can see the permissions by entering the command, ls -al. You may change permissions using the chmod command.

parent directory

The directory located above the a given directory in the filesystem hierarchy. The parent directory of the current working directory can always be accessed through the special .. directory (visible with the ls -a command).

Examples:

/usr is the parent directory of /usr/share
/, the root directory, is the parent directory of /bin

path

The specification of a file in terms of the where it is in the hierarchy of directories in the filesystem. This specification is relative to the root directory if it begins with a slash(/) or relative to your current working directory if the beginning slash is omitted. A full path is generally one specified relative to the root directory and so always begins with a slash (/).

Example paths:

    /           the root directory
    .           your current working directory
    ..          the directory above your current working directory
                (the parent directory)
    /u/smith    user smith's home directory
    /u/smith/.cshrc   the full path of the .cshrc file in user smith's home directory
    bin         a directory named bin which is a subdirectory of the 
                directory you are currently in
    /bin        a directory named bin which is a subdirectory of the 
                root directory
    ../bin      a directory named bin which is a subdirectory of the
                directory above you (the parent directory of your
                current working directory)

root directory

The top (or bottom depending upon how you look at it) of the directory hierarchy in the filesystem. All directories and files branch off of the root directory. The root directory is specified with a path of just the slash: /

shell

The UNIX shell is the interface between the user and the operating system. The shell, amoung other things, presents the UNIX prompt to accept user commands.

telnet

One way of connecting to another machine (usually a UNIX -based machine) over a network using a text-only (no graphics) interface.

From a ethernet-networked Macintosh, telnet can be accomplished using the applications MacIP, NCSA Telnet or MacSampson.

From a ethernet-networked IBM-compatible, telnet can be achieved using LAN Workplace for DOS or NCSA Telnet.

From a Sun workstation, the telnet command can be used.