DV C151 Lab 1

Dana Vrajitoru
C151 Multi-User Operating Systems

Lab 1

Due Date: Tuesday, January 17, 2012.

Ex. 1.
Make sure you get an account for our Linux filesystem from me. If you already have one from a previous class, you don't need a new one.

Tools

On a Linux machine you will need a terminal. Where it is located depends on the system. You can find it under the Applications menu - Accessories under Ubuntu. On Fedora you need to clock on Activities, then Applications, then scroll down to find the Terminal.

On a Windows machine, you need to install a program like Putty. On the campus machines, it can be found under the All Programs - Putty. At home, follow the link to the Putty download page (http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html). Right-click on the link for putty.exe and choose Save Target As (Explorer) or Save Link As (Firefox). If you save the executable putty.exe on a flash drive, you can run it on any computer without having to install it.

On the MacOs you can use the Terminal application that is part of the standard system installation. On the campus machines it should be in the dashboard already (the icon looks like a monitor). At home you should find it either directly under Applications or under Applications - Utilities.

Starting up. Follow the instructions for the type of system that you are working on.

On a Linux machine, log on and launch a terminal.

On a Mac machine, launch a terminal and then run the command:
ssh cs##.cs.iusb.edu -l username -XY
where ## means a 2-digit number between 01 and 30. Substitute username by the account name you were given. This opens a remote secure session on the machine that you specified. You will be prompted for a password. You may have to try several numbers to find one that works because some of these computers may be booted in Windows or MacOS, in which case they will not respond to this command.

Example (connectMac.gif).

On a Windows machine, launch Putty and type the following as the Host Name:
cs##.cs.iusb.edu
where ## means a 2-digit number between 01 and 30. Make sure that the connection type is SSH. Example (putty1.png). You may be asked a security alert system the first time you log on to a particular host, like in this Example (putty2.png). Just answer yes. A terminal window will open where you will be prompted on a second screen to enter your username and password, like in this Example (putty3.png). These should be the ones you get from me. You may have to try several computer numbers until one works (see Mac section above).

On your home computer, you may want to bookmark the session information for easy access. You can enter the username and remote host name, then give is a name easy to remember in the Saved Sessions box, and click Save. After that you'll be able to launch the session again by double-clicking on the bookmark name in the list. It is not recommended to save the password.

Ex. 2. Introduction to some shell commands.

A command is a small executable that perform some operation involving the file system, processes, operating system. For example, the command "ls" stands for "list" and will display a list of the files contained in the working directory.

Commands can have arguments specifying what they apply to. For example, for the command ls, we can provide a different directory that the active one to display the contents of (/var/log/ in the following case):
ls /var/log

Commands can also have options that modify the way they are executed. For example, an option for the command ls would be "-l" that makes it display the list of files with a long list of arguments:
ls /var/log -l

If you are not sure about what a command does and what options can be used with it, the easiest way to find out is with the command "man", which is short for manual (q to exit):
man ls

Commands we'll use below:

ls - displays the list of files in a directory
cd - changes the current working directory
pwd - displays the path of the working directory
less - displays the content of a file one page at a time
mkdir - creates a directory
pico - simple text editor
cat - displays the entire content of a file
cp - copy a file or directory
rm - remove a file or directory
man - manual pages (q to exit)
alpine

Practical:

If this is a new account for you, it is recommended to change your password. Use the command "passwd" for this purpose. The rules for the passwords are about the same as for any modern password system - it should be at least 8 characters long, should contain at least 1 uppercase or digit or special character and should not be based on a word that can be found in a dictionary.
Try out the command ls with and without the option -l. Explore the content of the directory /usr/ using this command.
Use the cd command to go to the /usr directory and move around it (cd /usr). Descend in the include directory and inside one of its subdirectories (your choice). To go back in the path you can use
cd ..
Find the path where you are using the pwd command.
Use the less command to view the content of one of the files in this folder (the file name must be an argument for less). To move around inside the text, use the space, Page Up, Page Down, and the up and down arrow keys. To quit the viewer, type Q.
Use the cd command with no arguments to move back to your home directory.
Create a directory named "c151" under your home directory. The command for this looks like this:
mkdir c151
Use the cd command to go inside this directory.
Create a text file using the pico editor. You can do that with the command
pico lab1pico.txt
Write a few lines in this file, then save them with the command Ctrl-o. When the program asks you for the file name, just press enter to keep the same name. When you are done, exit the editor with the command Ctrl-x. Note that most useful commands for pico are displayed at the bottom of the window, where the "^" symbol means Ctrl.
Display the content of this file with the command cat. You only need the filename as its argument.
Use the cp command to make a copy of this file under a different name. First, find out how to use the cp command using the Linux manual for it. For this, type the command
man cp
The manual pages are displayed with the less commands, so you can use its functionality to move around the text.
Use this information to make a copy of your file under a different name, like hw1_copy.txt.
Use the rm command to remove the file that you have copied.
Explore the commands that you have just executed using the right-hand-side slider of the terminal window.
The Linux shell helps you type your commands faster. The tab can be used to complete a command that you are about to type. To test this feature, list the content of the /usr directory by typing
ls /u
and then without completing the word "usr", type a tab. Note that the shell has completed your command. Without pressing enter, type an "l" as if you were going to list the files or folders starting with l, and then press a tab again (you may have to press it twice). Since there are several folders starting with l, the shell will display all the possibilities instead of completing the command. As soon as the command can be completed uniquely, the shell will do it. For example, type an "o" and press a tab again. Since "local" is the only possible completion, the shell will complete it for you. Finish the command by pressing enter.

Ex. 3 Saving the content of your terminal.

On a Linux machine, open a gedit separate window by typing the command (the ampersand is important)
gedit &
The using the mouse, select the entire content of the terminal (which should copy it, but if that doesn't work, the Edit menu should let you copy), then paste it into gedit with Ctrl-V. Save it under the name lab1term.txt.
On a MacOS system, locate the Shell menu at the top of the screen (not of the terminal window) and then do Export Text As... Save the file as lab1term.txt.
On a Windows machine under Putty, click on the Putty icon in the top left corner, and choose Chopy All To Clipboard. Then open a simple text editor like Notepad and paste the content in a new file. Save the file under lab1term.txt.

Ex. 4. Using alpine to send an email.

You have an email related to your cs account, and your address is username@cs.iusb.edu.
Launch alpine by typing this command (and press enter). Note: some computers might still be running the previous Fedora core. If the command alpine doesn't work, use pine instead.
If this is the first time you have used alpine, the program will ask you if you want to be registered as a alpine user. Just press enter.
To find the content of your inbox, from the main menu (that you can always find with m), press enter or l for list, and then enter again. Your inbox is probably empty for the moment.
Start composing a message by typing c. In the To field insert my email address, danav@cs.iusb.edu. Move between the fields using the arrow keys. In the subject area, type lab 1. The body of the message should just state your name.
Attach the file called lab1.txt that you have created before. For this, move to the Attchmnt field and type Ctrl-t. This will take you to a file browser that should open in your home directory. Move between file names with the arrow keys. Locate the folder named c151 and when its name is highlighted, press enter. This should take you inside that directory. Select the file and press enter.
Once your email is ready, type Ctrl-x to send it. Alpine will ask for a confirmation and you can just press enter.
Note that most useful commands under alpine can be found at the bottom of the window, just as for pico. And just the same, "^" means Ctrl.

Submission. Submit the file lab1term.txt containing the text in the terminal for exercise 2 to Oncourse. Under Assignments 2 there is a section called Lab 1 where you can submit it. The due date for this lab is next Monday at 11:59pm.