Computing Tools and Resources

You can use the SSH command from a command prompt or terminal on any of the major operating systems to access CS Linux systems. You will want to connect to the Titan system (titan.cs.uregina.ca) as this is accessible from anywhere on or off campus.

You would type in at the terminal:

ssh <your-username>@titan.cs.uregina.ca

Replace <your-username> with your University of Regina username using all lowercase letters.

You will be prompted for your password for your CS Linux account. Once you enter your password you will be on the Titan Linux system. (This assumes this isn't your first time using your CS Linux account, see the Using CS Linux account the First Time below.) From here you can create files, directories as required.

Each Linux system has an online manual that you can access using the man command (e.g. man ls). You can also get help about the 'man' command by using: man man on the command line.

Some basic Linux command line commands you may be using:

• ls - list directory contents
• mkdir - make a directory
• cp - copy file(s) or directory to another location
• mv - move a file(s) or directory to another location (or rename file or directory)
• rm - remove a file(s)
• touch file.txt - create an empty file name file.txt
• nano file.txt - edit file.txt using the nano editor
• vim file.txt - edit file.txt using the ViM editor

When you want to disconnect from the system just type exit at the command line and you will be logged out of the CS Linux system.

Using your CS Linux account the First time

After you enable your account using the CS Services Account page you will be given a temporary password you have to use to login for the first time.

Once you use SSH from the command prompt or terminal you may be asked, The authenticity of host 'titan.cs.uregina.ca (142.3.200.160)' can't be established ... Are you sure you want to continue connecting (yes/no/[fingerprint])? You will want to answer yes to the question. This question typically appears only the first time you have used a computer to connect to Titan for the first time.

After answering yes to the above question you are prompted for the password for your account, this is where you will use the given temporary password received from the CS Services Account page above when you enabled your account.

You will be using this password twice, once to login and then once again to validate your current password to begin the password change process.

You are then prompted for a new password for your account. You will be asked to retype your new password and if you didn't run into any errors you are logged into the command line of the CS Linux system. The new password rules can be found on the CS Services Account page.

NOTE: As you type your password, the characters are not displayed as you type. Carefully enter your passwords while you are connecting to your account.

The above process will be repeated any time you use the Reset Password and/or Enable option as part of the CS Services Account page for your account.

Other Software you can use with your CS Linux Account.

There is other free software you can use to assit you with working with your CS Linux account via transferring and editing files. All this software is available for free for any of the operating systems.

FileZilla

You can download the client for FileZilla. This will help you transfer files from your computer to your CS Linux Account. When setting up a connection in the Site Manger you will want the following settings:

• Protocol: SFTP - SSH File Transfer Protocol
• Host: titan.cs.uregina.ca
• Logon Type: Ask for password
• User:  <your CS Linux account username>

You can then connect to Titan with the software. Your local computer directories will be on the left and your CS Linux account directories will be on the right after a successful login. You can then transfer files from either system via the software.

Visual Studio Code

Visual Studio Code (VS Code) is a text editor and much more. With the Remote Development extension pack installed for VS Code you can SSH to Titan using the Remote Explorer menu option.

You will be able to edit files directly on Titan using VS Code as your file editor. Any development you do for class work you will need to connect to that system (langs, os1 etc) instead. You can also use the terminal window as part of VS Code to access other CS Linux systems.

When always setting up a SSH connection you will want to have the following:

• Host: titan.cs.uregina.ca
• User: <your CS Linux account username>

Once you Login to Titan you will be able to access other Computer Science systems by SSHing to the system name.

Example:

ssh langs

will log you into the langs system.

Some brief information about the other systems is below. You must have a CS Linux account before you can access any of these systems. If you cannot login to Titan you will not be able to login to the other systems.

langs (langs.cs.uregina.ca)

The langs (languages) system will provide you with a few different programming languages you can use to write code.The languages that are currently provided are:

• C/C++
• gprolog
• java ( 8, 11, 17) via openJDK
• python 3.8 and 3.9
• racket
• LISP
• Perl
• Golang

os1 (os1.cs.uregina.ca) and os2 (os2.cs.uregina.ca)

The OS1 and OS2 systems are mainly used for CS 330 class. They are both configured to be able to support all the CS 330 class and lab work.

webdev (webdev.cs.uregina.ca)

The webdev system is used for developing PHP applications with a local MySQL database. It is typically used in CS 215 class but can be used by anyone. You require a php_web directory in you home directory for the web portion to be served correctly. You will have to connect to this system directly if you need to access your MySQL database on the system.

CL 115 Linux Desktops

You will also be able to access your CS Linux account by using one of the desktop systems in the Classroom building room 115. You can use any one of the systems with your CS Linux account.

Appropriate Use of Computers in Computer Science

The Department endeavours to provide and maintain computing resources for graduate and undergraduate students in various labs and offices. Equipment problems should be reported to Service.Desk@uregina.ca so that our technicians can implement repairs. Use this email also if you have system problems with Linux machines.

The computer facilities in the Department of Computer Science are provided for use in research and teaching only. Their use is governed by Canadian Law, University policy (including sexual harassment policy) and the Human Rights code. Individual users are responsible for compliance with these laws/policies. Users are expected to respect the privacy of other users. Tampering with or monitoring of user or system data on computers or networks is unacceptable.

Users violating use policies, applicable law and policies, or privacy guidelines will lose computer privileges.

Usage Policies

CS Linux Account policies are subject to change at any time.

NOTE: Linux user accounts are case sensitive. By default your user account will be all lower case characters, even if your username is displayed with upper case characters anywhere.

Your Linux account provides access to the Computer Science Department's Linux systems. These systems are used throughout the Computer Science courses for research and teaching purposes. Specifically you will be able to access Titan (titan.cs.uregina.ca) via SSH as well as use any of the Linux desktops in Classroom Building Room 115.

Linux Account Lifetime (creation, removal, and extension)

Your account is created when you register for a CS course and/or are majoring in a CS discipline. By default all student accounts start out as disabled. You have to access the CS Services Account page and enable your account to be able to start using it.

On the CS Services Account page there is an "Account Expiry" field, this will indicate when your account will be deleted. All associated data for your account will be removed on this date as well. Please save any directories/files from your account before this date.

Your account expiry will be extended each semester you register for a CS course or are contiuning majoring in a CS discipline. Once you stop registering for CS courses or change majors away from CS, your account will eventually expire. You will be notified via your uregina.ca email a few times before your account is about to expire.

Typically your account lifetime is 1 year plus 1 semester after the end of the semester you were in a CS course or are pursuing a major in a CS discipline. For example, if your account was created Winter Semester 2024 your accout will expire approximately middle September 2025. This is assuming you did not register for any CS courses and are not continuing along as a CS Major. If the account expiry occurs, the next time you register for a CS course you will have an account created for you minus all your previous work.  Save any of your data (files, code, directories etc.) to your own system/devices before your account expires.

You can also lose your account by abusing your account in such a way that it does or could interfere:

• with those using the machine for classwork
• with the proper functioning of the machine under any circumstances

Disk Usage

Your Linux account has disk quotas in place to limit the amount of space associated to everyone. The quota is currently set at 3 GB.  You can check your own disk quota and usage by entering the command: quota -s once you login to any CS Linux system terminal.

All accounts are checked daily to ensure that they have not exceeded their quota. If any account is found to be over quota you will be notified via email. You will have 7 days to clean up the disk usage in your account.

You can run the command: du -ch --max-depth=1 at any CS Linux system terminal in your home directory to view which directories are using the most space. Repeat the command as required in other directories to narrow down your search if needed.

Some typical directories you can look in and safely remove files (using the rm command):

• On desktop (CL 115) empty your Trash Directory.
• Check your Downloads folder and remove files in there
•  remove any files beginning with "core-", typically in your home folder could be in others as well.
• .vscode-server/extensions directory can be emptied (used when connecting remotely with VS Code). These extensions will be reconfigured when you connect remotely to a system through VS Code.
• .vscode/extensions directory can be emptied (used when using one of the desktops in CL 115 VS Code). If you delete extensions in here, you will have to install the extensions again if you are using one of the desktops in CL 115.
• .cache/ you can remove all files/directories in here
• If you use the CPP extension in VS Code, you may have to set the "C_Cpp Intelli Sense Cache Size". By default this is set to 5000. Which is 5 GB and more than your quota. Please set this value to 512. You can find the setting by going to File -> Preferences -> Settings in VS Code.  Then you can search for the IntelliSenseCacheSize  setting and ensure it is set to 512.

You can also use the tar command with -z flag or zip command to group files and compress them to a single file archive. Then transfer the archive to your own device and remove the archive locally. However, you will need to have some space in your account to be able to support the size of the archive file.

If your account is left in an over quota state you may not be able to continue your course work or even login to a CS Linux system.