(Possibly) useful tech links/notes

General linux tutorials

Creating your own videos (for projects etc)

Student account information

On VIULearn, your instructor will post an assignment named something like "CSCI Credentials", which will simply ask you for your name and student number. When the instructor "marks" the assignment, they will return your account information as the feedback.

This assignment can also be submitted by returning students, but the only account information the instructor will be able to supply is your linux loginid.

Student password resets Important information about how to initiate communications that involve privileged information with the CSCI Technician. This includes: password resets, account problems, unable to connect to server. NOTE: if your instructor has not yet given you your csci login and password DO NOT USE THIS PROCESS TO GET IT. Please wait until it is handed out to you by your instructor. The following is only to be used if there is a problem AFTER YOU HAVE BEEN GIVEN YOUR CREDENTIALS. Suppose something goes wrong, and you need to ask Merlin to reset your password or fix your csci account, what should you do??!! Here's the plan for handling these kinds of requests, so that we can: 1) trust who it is coming from 2) send information in a secure manner HOW TO INITIATE SENSITIVE REQUESTS WITH TECHNICIAN: All sensitive account requests (password resets, unable to connect, account troubles) must go through VIU Learn, as follows: 1. Log into VIU Learn and navigate to one of your courses. 2. Select Communication -> Classlist 3. Locate Merlin Hansen (Instructor) in the list. 4. Click the down arrow beside Merlin's name and select Send Email. 5. Enter an appropriate subject (example: Please reset my CSCI password). 6. Enter an appropriate message in the Body and include your: 1. Name and student number. 2. CSCI Linux username (if known). 3. What CSCI course(s) you are enrolled in. 4. A detailed description of the issue you are having. 7. Note: Do not provide your old password or what you recall as your password. A good SysAdmin will never need or ask for your password. 8. Click Send 9. Wait for a reply from your Friendly Neighbourhood SysAdmin. Upon receiving a request such as above the CSCI Technician will 1. Verify the information provided by the student including confirming identity and enrolment status. 2. For a password reset request: 1. Generate a new one-time-password. 2. Generate a one-time-viewable message containing the new password, the student's username, or both (as the situation requires). 3. Send a reply to the student via VIU Learn containing a custom URL pointing to the one-time-viewable message, and/or any relevant information or queries. If you have any questions or concerns about this, please forward them to the department chair (chair@csci.viu.ca) or technician (tech@csci.viu.ca) for clarification.

Transferring files between your laptop/pc and the CSCI servers

• If you have a mac, win10, or linux laptop/pc

  On linux open a terminal window, on a mac go to Applications->Utilities->Terminal, on windows 10 run the Ubuntu app.

  You can then use the scp program to transfer file as follows (you will be prompted to enter your csci password):
  to transfer files from the your laptop/pc to the csci server
      scp thefilename yourloginid@csci.viu.ca:thefilename
  to transfer files from the csci server to your laptop/pc
      scp yourloginid@csci.viu.ca:thefilename thefilename
  Note that you can also specify a path to where the file is/should go on either machine

• If you have an older version of windows
  First, download pscp.exe (freely available from www.chiark.greenend.org.uk/~sgtatham/putty/download.html
  Open a command prompt (start/run) and enter one of the commands below (you will be prompted to enter your csci password):
  to transfer files from the your computer to the server
      pscp thefilename yourloginid@csci.viu.ca:thefilename
  to transfer files from the csci server to your computer
      pscp yourloginid@csci.viu.ca:thefilename thefilename
  Note that you can also specify a path to where the file is/should go on either machine
  *Note: you may also need to specify the port, e.g. -P 22

  Alternatively, check out WinSCP .

Auto-formatting C/C++ program layouts

First, copy the following file to your home directory: .indent.pro
The changes will be usable the next time you login.
(You only need to do the copy/save this once.)

Subsequently, whenever you want to auto-reformat your C++ code, use the following command:
indent oldfilename.cpp -o newfilename.cpp
(e.g. indent lab5a.cpp -o lab5b.cpp

If you then wanted to rename the auto-formatted lab5b.cpp to lab5.cpp (for example), you can then use the move command syntax: mv oldname newname, e.g.
mv lab5b.cpp lab5.cpp

Accessing VIU Windows lab machines from home

Accessing CSCI machines from home

On a mac, go to Applications->Utilities->Terminal, and in the window that opens use the command
ssh -l youruserid csci.viu.ca
(after which it will prompt you for your password)
Note: the -l is a lowercase L, not a one

From a linux machine simply open a terminal window and use the same ssh command shown above.

For use from a phone or tablet, there are often apps that can be used similarly (e.g. ConnectBot for android) - Searching for 'ssh' apps is probably the best starting point.

For those running Windows 10, holding down the Windows key and hitting X will bring up a menu from which you can select PowerShell. Within the resulting PowerShell window you can enter the same ssh command as is listed above for linux/mac.

For those on older Windows machines, another commonly used program is PuTTY, which is freely available for download.

When connecting use port 22 and the host name csci.viu.ca, and you'll be prompted to enter your userid and password)

Once connected, you will have your command window to work in, very much like the terminal windows we open in the labs.

Important note: the gedit editor won't work when connecting this way. There are a number of other editors that can run inside your open terminal window - emacs, nano, and vim to name a few. vim and emacs both have a bit of a learning curve to them (but are ultimately worth knowing), nano might be the easiest to get started with. Thus to edit a file you would type nano filename instead of gedit filename nano uses the control key to issue basic commands, e.g. control-X to exit, control-G for help, control-O to save (writeout), etc. A short menu of command options can be seen at the bottom of the window while you're working in nano. Alternatively, see Humayun's guide to installing X2Go, which will allow you to use tools like VSCode and GEdit on our servers but using your home machine.

Accessing CSCI machines from smartphones

Connecting from a smartphone is much like the access from home section above, it's just a matter of getting the correct app installed first. There are a variety of apps out there, including ConnectBot for android, ssh for iphone, and BBSSH for blackberry.

Access to CSCI labs

Using email on the CSCI servers

• (Omit this step if you're already logged in to otter)
  Enter the following command to connect to our server otter:
  ssh -Y otter

• Type in your password when prompted

• Enter the command
  alpine

• You will find yourself in a text-based email program, with the menu commands listed on screen.

• Once you are finished, quit alpine (Q), and logout of otter (logout)

Accessing Discovery U-drives from CSCI machines

This document describes how a Computer Science student can access their DISCOVERY U: drive from an Xterminal in 315-102. The same basic procedure probably works in 315-115, but this is untested.

Steps:

1. Login to a Linux system in 315-102 or 315-115.

2. From the main menu select: Places->Connect to Server...

3. Select Service Type: Windows share

4. Set Server: dolphin.discovery.mala.bc.ca

5. Set Share: users$

6. The folder name consists of three components based on your student number - the second last digit, the last digit and the student number itself, separated by slashes. For example, if your student number is 123456789, set Folder: 8/9/123456789

7. Click Add bookmark

8. Set Bookmark name: UDrive

9. Click Connect - you should get a file browser window with the contents of your DISCOVERY U: drive.

Notes:

1. To copy files or folders from one system to the other, the only method that appears to work consistenly is Copy/Paste: right click on the item you wish to copy and select Copy, then right click where you wish to move the file and select Paste. You can bring up a file browser with your home directory, from the main menu select Places->Home Folder.

2. Some files, such as (some) PDF files, can be opened directly from the U: drive, others probably need to be copied.

3. On subsequent logins, if you create a file browser (Places->Home Folder) you should be able to click on UDrive in the lower left pane to access your DISCOVERY U: Drive.

Trouble-shooting git submission issues

• Error message: fatal: not a git repository
  *Possible problem/solution: you tried to run "git push" when you weren't in the directory for that lab/project, cd into the directory then try again

• Error message: fatal: down for backup
  *Possible problem/solution: the git server is actually temporarily down while backups are performed, the only solution for this one is to wait awhile for the backups to complete then try again.

• Error message: fatal: W any csciNNN/assignment username denied by fallthru
  *Possible problem/solution: here NNN would be your course (e.g. 265), assignment would be whatever the repo is called (e.g. lab1) and the username would be yours. When you try to push, it should be trying to push to csciNNN/username/assignment (your space for that assignment on the server). What this message indicates is that you originally cloned the wrong repo (typically you needed to run git clone csci:csciNNN/$USER/assignment you probably actually ran git clone csci:csciNNN/assignment). To fix this, we need to tell it where it should try to push to in the future, which can be done with the command git remote set-url origin csci:csciNNN/$USER/assignment (substituting the correct course number for NNN and the real repository name instead of assignment)

• Error message: fatal: out of memory, malloc failed
  *Possible problem/solution: your repository contains some large files, and git is trying to allocate enough memory to include those in your push. Note that the cubs and pups let you use more memory than otter, so (as with most of our work) you're better off doing your work (including pushes) on the cubs/pups rather than directly through otter.
  *Prevention: in general, avoid using git add . to add files to tracking, since this adds everything in the current directory. If you use git add filename on the specific files you want tracked then you can be much more selective.
  *Analysis/cleanup: you can see which files git is tracking using the command git ls-files, which in turn lets you see if any are large and unnecessary, in which case you can use git rm filename to both get rid of the file and tell git to stop tracking it.

• Checking git status: if you run the command git status from inside your repository, it will give you a clear idea of whether or not you have done all the necessary adds/commits/pushes as far as git knows:

  • git status message: up to date with origin/master
    *Possible problem/solution: no problem, things look good!

  • git status message: ahead of origin/master by N commits
    *Possible problem/solution: you've done your adds/commits, but a git push is still needed

  • git status message: changes to be committed
    *Possible problem/solution: you've done your adds, but still need to do a commit before your push

  • git status message: untracked files
    *Possible problem/solution: you've created/modified some files but have not done a git add for them. If you want them to be included in the push then you need to git add them (then commit, then push)

  • git status message: you have unmerged paths
    *Possible problem/solution: you've begin merging two different git branches, but have not yet resolved conflicts in one or more files (the status message will list the filenames). You need to edit each of the files, making sure they contain the exact content you want, and save each. Note that git will have added a set of lines like the following, which need to be removed as part of your editing process.
    <<<<<<<<<<<<<<<
    ===============
    >>>>>>>>>>>>>>>

Disk quotas for student accounts

You can check your quota and current usage using quota -sp

If you're over the limit you'll need to hunt around for any large files causing the issue.

A useful pair of commands for finding large files or directories is
du -k | sort -n | tail -20

You can use the rm filename command to get rid of an offending file, or drag it to the Trash icon and empty the trash (the space isn't freed until you actually empty the trash).

Problems often come about due to web browsers storing a large amount of data in the cache - you can dig around the preferences for your chosen browser to find the right option to limit that (if desired) or find and remove their cached files (e.g. for chromimum look in ~/.cache/chromium, for firefox look in ~/.cache/mozilla)

If problems arise from having too many files (a less frequent problem, but students can sometimes exceed their limit), you can find directories containing many files using
find . -printf '%h\n' | sort | uniq -c | sort -k 1 -n | tail -20

Running Debian in a virtual machine on your laptop

One option is to create a virtual machine on your laptop, and install/run debian linux "inside" that. One widely-used (free) tool for installing/running virtual machines is VirtualBox. Installing VirtualBox is relatively painless, and you can then install/run other operating systems within virtual environments.

A guide to installing Debian through VirutalBox is available here: (BrianLinkLetter)

Simulating the lab's X-server on your home machine

Two free solutions are to install either

• install cygwin (including its x windows), configure and start it, or
• install virtualbox and then do a linux install

You can then start an xserver in whichever you installed, open an xterm window through it, then run this command to connect to our server:
ssh -Y -l yourusername csci.viu.ca
(that's an uppercase letter Y and a lowercase letter L)

At that point you can start up the tools you would usually use in the lab (gedit, wish, etc) and the display will show up properly (though perhaps slowly) on your home machine.

VS Code 1.49: bug causing ssh connection failure

• output of ssh connections report:
    - Installation already in progress
    - unable to obtain lock
• when an ssh connection is attempted it hangs on installing server
• if you look in your folder in otter you will see a .vscode-server folder but it only has 1 file in it and it is empty.

• Set the remote.SSH.lockfilesInTmp option to true
  File -> Preferences -> Settings
  enter "remote.SSH.lockfilesInTmp" in the search bar
  Check the option to enable (set it to true)

What happens if the above does not work....

• Shutdown VS Code
• Use the command line or PuTTY or similar to ssh into csci.viu.ca
    - remove or rename the folder ~/.vscode-server
• disconnect and try VS Code again

[Security]
EAP-Method=PEAP
EAP-Identity=yourstudentnumberhere@viu.ca
EAP-PEAP-Phase2-Method=MSCHAPV2
EAP-PEAP-Phase2-Identity=yourstudentnumberhere@viu.ca
EAP-PEAP-Phase2-Password=yourpasswordpasswordhere

[Setting]
Autoconnect=true

$ iwctl
[iwd]# station *device* connect viu-secure

CSCI GitLab server [BETA] available

CSCI now has its own GitLab server available for CSCI faculty and students. 

You will need to request access to the server by sending a message to the CSCI
Technician via D2L. Once approved you will be able to log into the CSCI GitLab
server using your VIU computer account credentials. NOTE: not your CSCI
credentials, but your student number and VIU password.

Server information:
- By default each student can have up to 10 repositories.
- The server is accessible from both the CSCI network and the Internet.
- The server URL is gitlab.csci.viu.ca

Note: I consider this service to be in Beta. What this means is that although I
will do my best to ensure the server is stable and available 24/7, it is not
guaranteed at this stage. Also, currently the server is not backed up offline.
This means that there is a very small possibility that your repos may be lost at
some point. However, so long as you have a local clone this is not really a
concern. I do not foresee a situation where repos will be lost but you have been
warned.

Future plans: The Beta will last then next few months depending on the adoption
and usage of the server. As time progresses I will fine tune and tweak the
server until it can be considered production ready.

NOTES:
- This GitLab server does not in any way replace the Git Assignment Submission
system used in some CSCI courses.
- Yes you can use this GitLab server to move code between your CSCI account and
your home computer.

If you have questions, please fire away. Please report any issues, no matter how
small, to me so that I can investigate them.

Another handy-dandy guide from our resident wizard, thanks Merlin!

If you are like me you love Markdown for use in documentation, all over the place. As great as Markdown is, viewing it in a browser as Markdown leaves something to be desired and converting it to HTML is a bit of a pain to maintain.

If you use Google Chrome or Firefox then there is a nice solution... a Firefox and Chrome extension that allows you to view Markdown files as either Markdown or as HTML:

Firefox: https://addons.mozilla.org/en-US/firefox/addon/markdown-viewer-chrome/

Chrome: https://chrome.google.com/webstore/detail/markdown-viewer/ckkdlimhmcjmikdlpkmbgfkaikojcbjk

Of course it is an open source project, and is hosted at https://github.com/simov/markdown-viewer

I've been running this extension for a couple of years now and have found it easy and useful (especially since I keep handing Dave Markdown files to put up on his Tech Notes page and write all of the CSCI documentation in Markdown). If you are interested, read on...

When you install the extension you will want to configure it to give it access to the websites where you want to view Markdown as HTML. By default it does not have permissions to access any websites, which is good. To give it access to pages hosted on csci.viu.ca when viewing them:

- click on the extensions icon in Chrome (the puzzle piece shaped icon)

- click on "markdown viewer" to pop up the options page

- click on "Advanced options", which will open a new tab showing the "Allowed Origins" configuration page for the extension

- click on the drop-down and select "*://" instead of "https://"
- enter "csci.viu.ca" (where it says raw.githubusercontent.com), and click "Add"

- the new entry will show up in the list lower in the page

Note: You will also see an entry in the list for "file://" which allows any locally stored Markdown file you view in the browser to be displayed as HTML via the extension.

Aside from Dave: essentially the same instructions work in Firefox except the symbol you're looking for is an "m" in italics instead of a puzzle piece

Now to view a Markdown page as html browse to a Markdown page such as: http://csci.viu.ca/~wesselsd/guides/Tutorial-sshClient.md, click on the puzzle piece and select "markdown viewer" again to bring up the options. Then click on the "HTML/MARKDOWN" toggle button two switch viewing the page in the two modes.

Hope you find this useful.