AFS Course Space

This page will describe the structure of the AFS shared spaces given to courses and will explain the process for setting up your account to use it.

Introduction

Prior to 2013, Duke's public computers used the Andrew File System to store files. This system allowed individuals to set seven different permissions to each folder within their space. Users could assign permissions to single users or to groups. While this system was extremely flexible, over time, support for it dwindled. In the Spring semester of 2013, Duke switched to CIFS as a file system. While this system has many positive features, it is entirely lacking in the ability to grant permissions to individual folders. It also does not allow for symbolic links. Given these drawbacks, and given the current lack of an alternate way for students and instructors to set up shared course spaces within CIFS, Duke is maintaining a section of AFS-hosted folders, specifically for courses.

Goals

The goals of using the AFS shared spaces are as follows:

• Allow for file sharing from the instructor to all the students in a class
• Allow the instructor and teaching assistants to access course-related files for students - this will facilitate both off-line assistance and grading

AFS Location

The AFS folders are all located at

/afs/acpub.duke.edu/courses/YEAR_SEMESTER/DEPARTMENT/CLASS

For example, the Spring 2013 offering of EGR 103L has a set of folders at

/afs/acpub.duke.edu/courses/2013_spr/egr/103l

Within the CLASS folder, there will be a folder for each section (for example, 002). For Dr. Gustafson's courses, however, students will not need to worry about the section folder, only the CLASS folder.

Personal AFS Folders

For Dr. Gustafson's classes, each student will have a folder within the CLASS folder. The folder will be the same as the student's NET ID. For example, in EGR 103L, a student with a NET ID of mrg would have a folder:

/afs/acpub.duke.edu/courses/2013_spr/egr/103l/mrg

If you find that you do not have a folder, be sure to check the directory. If you are in the correct directory and still do not have a folder, let Dr. G. know.

When these folders are created, permissions are set as follows:

• system:administrators and mrg have all permissions
• the student and the TAs have read, list, insert, delete, write, and lock permissions, but not administer permissions
• no one else has any other permissions

Fortunately, whenever a new folder is created, it will take on the permissions of the folder in which it was created. In other words, as long as the student always first changes into the shared AFS space, everything created there can be seen by the student and the instruction team.

There is also a folder called public within the CLASS directory. For this folder,

• system:administrators and mrg have all permissions
• all students and TAs have read and list permissions

This way, files that students need to copy can be hosted in the shared space and all students can copy the file without any chance of accidentally (or intentionally) removing those files.

Shortcuts

One problem with the CIFS is that it will not allow symbolic links, or shortcuts, to folders. In other words, to get to the public space for EGR 103L, a person would have to type out

cd /afs/acpub.duke.edu/courses/2013_spr/egr/103l/public

every time (unless a path using .. were available).

To make life a little easier, you should create an alias that changes into your space within a particular class. NOTE:THE SHORTCUTS DEPEND ON WHAT KIND OF SHELL YOU ARE USING. To check, type

echo $SHELL

in a terminal window. If your shell is /bin/bash, follow the first set of instructions; it it is /bin/tcsh, follow the second.

For /bin/bash (newer users)

To create a set of aliases, you will first need to make sure that the system checks a configuration file called .bashrc whenever you log in or make a terminal window. You will therefore need to create a file in your home directory called .bash_profile that contains the following:

# start .bash_profile
if [ -f ~/.bashrc ]; then
	. ~/.bashrc
fi
# end .bash_profile

Type

emacs ~/.bash_profile

copy the above into it, then save that file. You should only ever have to do this once.

Next, you will add the aliases to the bash configuration file, called .bashrc. To do that, type:

emacs ~/.bashrc &

The file may be empty to start with or it may have some other items in it. Regardless, go to the very bottom of the .bashrc file and then add something like the following:

alias Go103='cd /afs/acpub.duke.edu/courses/2013_spr/egr/103l/NETID'

where NETID is your NET ID. For Dr. G's 2013 courses, use the following:

• EGR 103L

alias Go103='cd /afs/acpub.duke.edu/courses/2013_spr/egr/103l/NETID'

• ECE 110L

alias Go110='cd /afs/acpub.duke.edu/courses/2013_spr/ece/110l/NETID'

• EGR 224L

alias Go224='cd /afs/acpub.duke.edu/courses/2013_spr/egr/224l/NETID'

• ECE 382 (note - no "L")

alias Go382='cd /afs/acpub.duke.edu/courses/2013_spr/ece/382/NETID'

After you have added the appropriate line, save the file and close emacs. Then, on the command line, type

source ~/.bashrc

You will only need to do this once; .bashrc generally runs whenever a new window is opened and .bash_profile - which will run your .bashrc - runs whenever you log in, so from this point forward, the alias will exist. To make sure it worked, type the appropriate alias name and it should take you to your space within the shared CLASS directory.

From this point forward, whenever you need to do work for a particular class, just use the alias to get into the space and then work as usual.

For /bin/tcsh (older users)

To do that, type

emacs ~/.cshrc &

Go to the very bottom of the .cshrc file and then add something like the following:

alias Go103 'cd /afs/acpub.duke.edu/courses/2013_spr/egr/103l/NETID'

where NETID is your NET ID. For Dr. G's 2013 courses, use the following:

• EGR 103L

alias Go103 'cd /afs/acpub.duke.edu/courses/2013_spr/egr/103l/NETID'

• ECE 110L

alias Go110 'cd /afs/acpub.duke.edu/courses/2013_spr/ece/110l/NETID'

• EGR 224L

alias Go224 'cd /afs/acpub.duke.edu/courses/2013_spr/egr/224l/NETID'

• ECE 382 (note - no "L")

alias Go382 'cd /afs/acpub.duke.edu/courses/2013_spr/ece/382/NETID'

After you have added the appropriate line, save the file and close emacs. Then, on the command line, type

source ~/.cshrc

You will only need to do this once; .cshrc generally runs whenever a new window is open, so from this point forward, the alias will exist. To make sure it worked, type the appropriate alias name and it should take you to your space within the shared CLASS directory.

From this point forward, whenever you need to do work for a particular class, just use the alias to get into the space and then work as usual.

Copying public files

Many times you will need to copy files from the public space into your own directory. For example, in EGR 103L, Lab 1 has several files you will need. Because symbolic links no longer work, you will just use .. to go up the directory structure the the CLASS folder, then down into the public folder. For example, if user mrg needs to get the Lab 1 files from the public directory and put them into mrg's own lab1 directory, that might be:

Go103

to get into the user's own egr/103l/mrg space, followed by

mkdir lab1

to make a folder for that assignment. Then

cd lab1

to get into the folder and, finally,

cp -i ../../public/lab1/* .

to go up two levels (the CLASS folder), then go into public and from there into public's lab1 folder. Don't forget the space and . at the end.

Questions

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