CS 101 - Lab 1

CS 101 - Introduction to Computing, Spring 2008

Lab 1

For this assignment, you are to create a simple web page on your CS account. You will need to have an account on the CS Department machines and be familiar with a few UNIX commands:

cd <directoryName> - change directory
ls - list directory contents
pico <fileName> - edit a file
exit - exit the icarus system

You may also wish to read the ACCC's Web Publishing for Beginners; however, you will find there are a few items that are different between the ACCC's computers and the CS Department's computers. The ACCC is the University Computer Center.

The main page regarding the CS Department Computers is found at: http://www.cs.uic.edu/~consult/.

When using the CS Department Computers, you are required to follow the CS Department COmputing Policy.

Using Your CS UNIX Account

The CS Department has two remote servers and 72 workstations. To use the workstations goto SEL 2250 or SEL 2260 (these workstation are actually running Linux and not UNIX). The remote servers are

bert.cs.uic.edu
ernie.cs.uic.edu

Every CS student and every student taking a CS course is given a can have an account on the CS machines. Your account name is provided on the lists posted in the CS Computer Lab or outside the CS Support Office in 927 SEO. You can also find out an Initially, your password will be your UIN which you should change as soon as possible.

From a Windows Machine, you should log onto the CS machines using SSH which stands for Secure SHell. The ACCC has some web page support for SSH. An alternative program to SSH is PuTTY. The added security of these programs is a level of encryption that the traditional telnet program lacks.

From a Macintosh machine, you should start a terminal window and the use the ssh command to connect desired machine. This would be done by the use of the following command:

     ssh userid@machineName

     where
        userid is the account name
     and
        machineName is the name of the machine you want

For Example, to log onto the CS 101 instuctor account on bert.cs.uic.edu the command would be:

     ssh i101@bert.cs.uic.edu

The userid for the CS 101 instructor account is i101.

Once you are logged into a machine, you will need to learn some basic UNIX commands to get around and perform various tasks. Again, the ACCC has some web page support for using its UNIX machine icarus. In particular the ACCC's web page UNIX 101 give a nice summary on various UNIX commands. The CS Department also has a summary at http://www.cs.uic.edu/~consult/how/unix.html.

The Basic UNIX Commands

The UNIX commands that you will need for this lab are:

exit - Log off
End your connection to UNIX. It is very important to disconnect when you are finished so no one else can come along after you and use your account.
ls - Directory Listing
List the contents of the current directory. Note: a UNIX directory is the same as a Windows folder.
The ls command has a special usage that will give more information about the files in the current directory. This is the long listing. This uses the -l option to the ls command:
```
ls -l
```
The first thing given on the long listing is the permissions for each file. This is important when making web pages viewable on the internet.
pico <filename> - Edit a file
Allows the contents of file in <filename> to be changed. The editor pico is the counter part to the email reader pine. The ACCC's web page combine these two programs together under the name of pine. For a web page with a description of pico and how to use it, check out the North Carolina State Pico Page or ther University of South Dakota Pico Page.
cd <directoryName> - Change Directory
Change to the directory given in <directoryName>. This command is normally used to change to a sub-directory of the current directory (change one level down in the hierarchical file system).
The cd command has two special usages. These are:
1. cd - Change to your Home directory
  By just typing in cd, you will change back to your Home directory from where ever you are at in the hierarchical file system. Your Home directory is the directory you are in when you first log onto the UNIX system.
2. cd .. - Move up to the Parent directory
  This command will move you up one level in the hierarchical file system. The directory that is one level up from the current directory is referred to as the parent directory of the current directory.

Other UNIX Commands

There a literally hundreds of UNIX commands and I doubt that anyone knows all of them. A few other UNIX commands that you may want to know are:

cat <filename> - Display file
Display the contents of the file indicated by <filename> to the screen.
more <filename> - Display file
Display the contents of the file indicated by <filename> to the screen one page at a time.
cp <filename1> <filename2> - Copy file
Creates a duplicate of the file in <filename1> with the name <filename2>.
mv <filename1> <filename2> - Rename a file
Renames the file in <filename1> with the name <filename2>.
rm <filename> - Remove a file
Deletes the file in <filename> from the current directory. Note: once a file is deleted is cannot be restored. So use this command with caution!
lpr -P <printerName> <filename> - Print a file
Sends the file in <filename> to be printed at the printer with name <printerName>. This command also has a ACCC web page describing its use. Note: The lpr command will assume the file is stored using the ASCII character format (i.e. plain text). So don't try to print files that are not plain text.
Also check out the lp command and the CS Department How To Print page.
pwd - Display Current Directory
The actual command stands for Present Working Directory. This command will list the full path name of the current directory. Each slash in the full path name represents one level in the hierarchical file system.
ls - Directory Listing
List the contents of the current directory. Note: a UNIX directory is the same as a Windows folder.
mkdir <directoryName> - Make Directory
This command will create a new directory with the name indicated by <directoryName> as a sub-directory of the current directory.
rmdir <directoryName> - Remove Directory
This command will remove/erase the directory with the name indicated by <directoryName> that is an existing sub-directory of the current directory. Note, the sub-directory must be empty (contain no files or other directories) before it can be removed.

Your CS Home Page

Your CS account will include space on the CS Department's web server. There is no web page in the space, so we will create a simple one for this assignment. You can access your homepage with the address of:

     http://www.cs.uic.edu/~USERID

where USERID is your own CS account name.

Your home page will be stored in the file called index.html in the directory WWW within your CS account. (A special note: the WWW "directory" is really a "link", but for now we will gloss over that difference.)

Once you log onto your CS account, you are in your "home directory". Type the command:

ls

to see what files and "sub-directories" are in you home directory. You should have a directory called WWW Now change to that directory by typing the command:

     cd WWW

Note that CASE is very important. The command cd must be in lower case and WWW must be in upper case. Now type the ls command to see what is in your WWW directory. The files in this directory are made available to the world by the CS web server. Most likely you will get nothing as a result since your account is probably empty. Your default web page should be in a file called index.html. To create this file (or change it if it does exist) type the command:

     pico index.html

This will start the pico text editor and will allow you to make changes to this file.

HTML Tags

When using an simple editor like pico to create or modify web pages, you will need to type in your own HTML tags to make the page display as you would like it to. For this assignment, we will only introduce one HTML tag: LINE BREAK.

All HTML tags start with an less than symbol, then contain the text that specifies the specific tags and end with a greater than symbol.

<br> - LINE BREAK Tag
The use of this tag will cause the text following the tag to start at the beginning of the next line. The web browser will attempt to display as much information on each as possible no matter what spacing the original HTML file has. The browser just put one space between words removing any extra spaces or new line characters. This makes the use of <br> important.

If the Text File Contains,	The Web Page Displays
Hello There ! How are you ?	Hello There ! How are you ?
Hello There! <br> How are you?	Hello There! How are you?
Hello There! <br> <br> How are you?	Hello There! How are you?
Hello There! How are you?	Hello There! How are you?
Hello There! <br> How are you?	Hello There! How are you?
Hello There! <br> <br> How are you?	Hello There! How are you?

Lab Assignment 1

Due: Friday 1/22/2008 by 11:59 pm.

Create (or modify) the file in the web directory of your CS account with the name of index.html. This file is to contain your name on the first line of the file. This line might state something like:
```
     This is the home page of Pat Troy.
```
After the first line, type in your favorite joke or quotation. You should have at least one blank line between the first line that contains your name and your favorite joke or quotation.
Use the HTML tag of <br> to insert line breaks where needed.
Verify that your file is viewable via a web browser at the URL of:
```
     http://www.cs.uic.edu/~USERID

where USERID is your own CS account name.
```
Once you have created your web page, send an email to the CS 101 instructor account at i101@cs.uic.edu that contains the URL for this assignment. The subject for the email must be something like CS 101: Lab 1 Submission. This part is very important to make sure your lab gets graded!

Troubleshooting

If your web page is viewable, then don't worry about the following information for now.

If you cannot view your file, the most likely error is that the permissions are not set correctly for your WWW directory or your index.html file. Odds are that the fault is with the permissions of your index.html file. This is were the ls -l command comes into play. The following information is also discussed in the ACCC's Web Publishing for Beginners in the "First Steps" section.

When I am in my WWW directory and enter the ls -l command, the result for my index.html file is:

     -rw-r--r--  1 i101 instruct  1270 Jan 15 22:08 index.html

The key part here is the -rw-r--r--. If the last 3 characters do not contain the r, the page won't be displayed. To fix this type in the following command while in your WWW directory.

     chmod a+r index.html

This command will change the permission to allow the web browsers to read the index.html file in your WWW directory.

There are other possible places were the permissions could be set wrong. One is at your WWW directory. To fix this we need a variation on the chmod command. Entering the following command sequence should solve any problems.

Type in the following command to make sure you are in your home directory:
```
   cd
```
To return from your WWW directory to your home directory always use the cd command as shown above. This is improtant since the WWW directory is really a link in your home directory.
Type in the following command to set the permissions for your WWW directory.
```
   cd WWW
   chmod a+rx .
```
Note the period at the end is a very important part of this command.
Type in the following command to make sure all of the files in your WWW directory are readable by a web browser:
```
   chmod a+r *
```

Grading Criteria

Name: 25
Quote: 25
<br> tag: 25
Uploaded to own webspace: 25

Total: 100