Table of Contents

I. Introduction to the UF Astronomy Computing Environment

The computing environment at the University of Florida Astronomy Department primarily consists of workstations running the Linux and Solaris operating systems. Linux and Solaris are implementations of the UNIX operating system. This document is geared toward new users in the Astronomy Department that will be using our UNIX workstations. Throughout this document, the generic term unix will be used when referring to both the Linux and the Solaris operating systems. We specify either Linux or Solaris directly when the material is specific to one or the other.

Your Astronomy Account

Services Offered
Rules and Policies

Astronomy account as opposed to Gatorlink account

The University of Florida will provide a Gatorlink account to every faculty, staff, and student at the University. Gatorlink accounts provide limited e-mail, internet dialup access, and access to the CIRCA computer labs. Additionally, there are some services at the university, such as the ISIS course registration system, which can only be used with a gatorlink account.

Your gatorlink and astronomy accounts are two seperate accounts. If you are having problems with your gatorlink account you will need to contact the UF Computing Help Desk either on the phone at 392-HELP (392-4357) or by visiting their offices in 520 CSE.

II. Unix Concepts and Commands

Both Linux and Solaris share several commands between the two operating systems. This section is intended to give a brief overview of several common unix commands and is geared towards first time users of a unix environment.

The C Shell

Directory Structure

File Naming Conventions and Wildcarding

File Ownership and Permissions

Useful File and Directory Related Commands

Compressing/Uncompressing Files with tar and gzip

It is very common in UNIX for a file that you download to be compressed with one or both of tar and gzip. A gzipped file has the extension .gz and can be uncompressed with the command gunzip file.ext.gz. file.ext.gz will no longer exist and will be replaced by the uncompressed file.ext. A tarred file has the extension .tar and can be uncompressed with the command tar xvf file.tar. Unlike after gunzipping files, file.tar will still exist, but the contents of the archive will be extracted with their full path. Commonly, tar files contain directories with several files in them. Most files you download on UNIX systems will be compressed with both tar and gzip and have the extenstion .tar.gz. These files can be gunzipped and untarred with one command: tar xvfz file.tar.gz. The z flag to tar tells it to gunzip the file as well. file.tar.gz will still exist, and the contents of the archive will be extracted with their full path.

You can also create your own archives with gzip and tar. gzip works the same way as gunzip: enter the command gzip file.ext and file.ext will be replaced with the compressed file.ext.gz. To create a tar archive, you use the tar command again, but with the c flag (create) instead of the x flag (extract). The first parameter tar takes is the archive name, and then you can list as many files and/or directories as you want. Therefore, tar cvf file.tar file1.dat file2.dat dir1 would create an archive of the files file1.dat, file2.dat, and the directory dir1, including every file in that directory and its subdirectories. The archive would be named file.tar. Again, if you want to directly create a .tar.gz file, you can use the z flag of tar to do this in one step.

Processes and Jobs

Each command you run in a UNIX environment spawns its own process or processes. These processes are all run simultaneously by the UNIX kernel, which is known as multi-tasking (something that is somehow still not fully implemented in Windows). The UNIX kernel keeps track of all processes running, dividing its time among them based on the priority of each process. The way this works is that UNIX will execute some instructions from process A, then set it aside and execute some instructions from process B, and so on, constantly switching tasks. Each process is assigned a unique process ID (pid).