CS201
Lab 1 - Introduction to Linux and C

Attendance at this laboratory is obligatory!

---

Objectives:

• Meet with your Graduate Teaching Assistant (GTA) in person and  learn what he has to say. The intro to the lab will cover: 1) GTA's teaching policies and expectations, 2) a brief comparison of C and Java, 3) basic rationale for using C/Linux/gcc/submit, etc.
• Get up and running using your account on the Linux operating system on a computer in the lab.
• Use the a2ps command to get hard copy of source files.
• Use an editor (pico, emacs or vim ).
• Use gcc to compile your program.

---

Readings:

• Read about Linux and a chosen editor on one of the Web references page.
• Some commands you may want to read about are: ls, cp, rm, mv, ps, chmod, mkdir, cd, ps, finger, ssh, ftp, gcc, and man.
• The emacs family has some nice features for programming, but you can use another text editor if you like. I think pico is quite friendly for the first-time users.    

---

Deliverables: (DUE BY THE END OF YOUR 2^nd LAB !)

• A hard copy of your answers to a set of Linux Questions (shown below).
• Submittal of your helloworld.c Makefile and answers files.

---

Lab Rules

• Everyone should work individually on each lab, unless you receive explicit instructions from GTA to collaborate. I do not mind you discussing the logical solution to problems BEFORE the lab, but not exchange of code of any type is allowed.
• If your GTA allows some level of collaboration on the particular assignment - please make sure to communicate quietly, so you would not disturb other students.
• If there are any readings listed on the lab page, you must read them PRIOR to lab. It is the easiest way to avoid becoming lost about what to do and how to do it.
• The lab assignments are due at the time stated next to the Deliverables. This may vary, so be sure to check this for each lab.
• The work you do in lab will show up on the related exams. It is strongly recommended that you do all assignments.
• Late assignments will not be accepted so make sure that you are prepared when coming to the lab.
• There is a lot of work to do in CS201. Remember, this is where you build a strong programming foundation, so do not fall behind.
• Sometimes, the labs may be slightly changed by your TA, if something is not working, etc. If you have done your lab before the lab period (what I would actually recommend!), make sure that you submit proper file. You want to be 100% sure that you submitted the right thing - show up for your labs and talk to your TA!
• For purpose of this lab - you all need to have a directory, named cs201 created at the root of your esus account. It should have sub-directories named with lab numbers (i.e. lab1, lab2, etc.) Number of lab directories should match number of websites with lab assignments (e.g. this is lab1). You are expected to keep all your files in cs201 directory until two weeks after the end of the current semester.

---

TO DO (for today's lab)

• Be sure your computer is running Linux. If not, reboot into Linux.
• Log in to your account
• Go to a directory you will use for cs201. (Create a separate one if you have not already done so, make sure to name it cs201).
• Create a sub-directory called lab1 to use for today's lab and change to that directory.
• Start up the editor of your choice
• $ pico (for the pico editor)
• $ emacs (for the emacs editor)
• $ vim (for the vim editor)

The emacs family has some nice features for programming, but you can use another text editor if you like. I think pico is quite friendly for first-time users.

• Answer the following questions as briefly as possible by typing the answers into the word processor buffer.

Make sure  your answers are numbered and appropriately ordered.

1. What does the shell prompt look like on your account?
2. Type ls. What did happen and why?
3. Explain how you made a directory called cs201.
4. Explain how you made cs201 your current working directory.
5. From your cs201 directory, describe three separate ways to go back to your home directory.
6. Navigate our Linux system enough to estimate the number of students currently "logged in" on esus. Write down the number and explain how you determined it.
7. Save this file with the name answers.txt.
• Now, build a program in C to do the following (See the HelloWorld. The file is in PDF format on purpose, as I do not want you to use "copy-paste" option. Sorry, life is brutal sometimes... :) ):
0. Print out the phrase "Hello World!"

• Once you have written your program in a text editor, save it as helloworld.c
• Create a simple Makefile for your program (See the MakeFile). Hint: Find out what is a difference between "gcc -o ..." and "gcc -c ..." (See the WebRefs).

0. Compile the program using make helloworld command.
1. If errors were reported, fix the program and re-make it until it compiles without errors.
2. Execute the compiled program (by typing helloworld, or $PWD/helloworld).
• Open your answers.txt file with your text editor and verify that it looks correct.
• Now print hard copy of your source file (i.e. helloworld.c), your Makefile, and your answers.txt file by typing: a2ps -P orca helloworld.c Makefile answers.txt
• Hand in your hard copy to the TA. Be sure to identify each page with your name and staple multiple pages together.
• Submit your assignment.

LAB 1 ENRICHMENT

• Try changing the helloworld program so it says "Happy New Year!" instead of "Hello World!".
• Try printing a line of astericks *************** before and after the "Happy New Year" message.
• If you wanted to use the C++ compiler instead, replace gcc with g++.
• Figure out what is the difference between "./helloworld" and "helloworld" commands, and when both commands act in the same way.