Purpose of this AssignmentIndex
Do not print this assignment on paper! On paper, you cannot follow any of the hyperlink URLs that lead you to hints and course notes relevant to answering a question.
This assignment is based on your weekly Class Notes.
- Practice with Permissions in Lab Worksheet #08 HTML
- Practice setting Umask.
Remember to READ ALL THE WORDS to work effectively and not waste time.
Introduction and OverviewIndex
This is an overview of how you are expected to complete this assignment. Read all the words before you start working.
- Complete the Tasks listed below.
- Verify your own work before running the Checking Program.
- Run the Checking Program to help you find errors.
- Submit the output of the Checking Program to Blackboard before the due date.
- READ ALL THE WORDS to work effectively and not waste time.
Create directory and file structure with the given Permissions on the CLS. Record the numeric (octal) permissions of each of the directories and files you create in the given record file on the CLS.
Using various Umask settings, create new directories that have a given set of symbolic permissions on the CLS.
You will create file system structure in your CLS home directory containing various directories and files. You can use the Checking Program to check your work as you do the tasks. You can check your work with the checking program as often as you like before you submit your final mark. Some task sections below require you to finish the whole section before running the checking program; you may not always be able to run the checking program successfully after every single task step.
When you are finished the tasks, leave the files and directories in place on both the CLS as part of your deliverables. Do not delete any assignment work until after the term is over! Assignments may be re-marked at any time on the CLS; you must have your term work available on the CLS right until term end.
The Source DirectoryIndex
All references to the “Source Directory” below are to the CLS directory ~idallen/cst8207/14w/assignment10/ and that name starts with a tilde character followed by a userid with no intervening slash. The leading tilde indicates to the shell that the pathname starts with the HOME directory of the account idallen (seven letters).
You do not have permission to list the names of all the files in the Source Directory, but you can access any files whose names you already know.
- Do the following tasks in order, from top to bottom.
- These tasks must be done in your account on the Course Linux Server.
- Your instructor will mark on the due date the work you do in your account on the CLS. Leave all your work on the CLS and do not modify it.
- Do not delete any assignment work from the CLS until after the course is over.
- READ ALL THE WORDS! and do not skip steps.
Set Up – The Base Directory on the CLSIndex
Do a Remote Login to the Course Linux Server (CLS) from any existing computer, using the host name appropriate for whether you are on-campus or off-campus.
Make the directory ~/CST8207-14W/Assignments/assignment10, in which you will create the files and scripts resulting from the following tasks.
Create the check symbolic link needed to run the Checking Program, as described in the section Checking Program below.
This assignment10 directory is the base directory for most pathnames in this assignment. Store your files and answers below in this base assignment10 directory.
Run the Checking Program to verify your work so far.
Part A – A file to record your permissionsIndex
You need to record the Permissions you set on each of the directories and files you create in the next Part, below. You will record these permissions by copying and editing a file that you get from your instructor. You can record each of the permissions as you create things step-by-step below, or you can record all of the permissions after you have finished, before you run the checking program.
Copy the file record.txt from the Source Directory into your own file abcd0001.txt (no spaces) where the text abcd0001 is replaced by your own eight-character userid in the file name. This file copy should be located directly under your assignment10 directory.
Fix the Permissions on the file so that you can edit it and nobody else (group or other) has any permissions at all.
As you work on the next Part below, edit your copy of the file with a text editor. (The vim editor is recommended, since that is the universal text editor for system administrators.) Replace each string of three underscores in the file with the correct three-digit numeric (octal) permission value that you record in the next Part below. Do not change anything else in the file. Note the word count at the bottom of the file. Your count must match exactly, at all times. If not, re-copy the file and start over.
Part B – Creating structure with permissionsIndex
Do the Permissions section of Lab Worksheet #08 ODT before continuing. Record all your answers for later quizzes.
Now you will create some directories and files, then set the correct permissions on them. The permissions to set are described below.
Because you are applying Permissions to directories as a non-root user, be careful not to lock yourself out of directories by restricting permissions on them too soon. First, create all the file and directory structure from the top of the directory tree down, and then apply restrictive permissions afterward from the bottom of the tree upward.
If you don’t apply permissions last, from the bottom up, you will deny yourself permissions that will prevent you from entering some directories lower down. Assign permissions from the bottom toward the top.
- Create a directory named
head under assignment10
- Directory
head has no permissions for others. The group can use ls to see the content, but cannot create files or cd into the directory. The user has full permissions. Record the permissions for head in the Record file.
- Underneath directory
head create three three-letter directories named: usr grp oth
- Directory
usr has no permissions for group or other. The user can cd into it, but cannot create any new content nor use ls to see any files in it. Record the permissions.
- Directory
grp has no permissions for user or other. The group can cd into it and use ls in it, but cannot create any new content. Record the permissions.
- Directory
oth has no permissions for user or group. Others have full permissions. Record the permissions.
- Underneath directory
usr create three two-letter files named: rd wr xc (You did create files, right?)
- None of the files have any permissions for group or other.
- File
rd has read permission (only) for the user. Record the permissions.
- File
wr has write permission (only) for the user. Record the permissions.
- File
xc has execute permission (only) for the user. Record the permissions.
- Underneath directory
grp create three two-letter files named: rw wx rx
- None of the files have any permissions for user or other.
- File
rw has read and write permission (only) for the group. Record the permissions.
- File
wx has write and execute permission (only) for the group. Record the permissions.
- File
rx has read and execute permission (only) for the group. Record the permissions.
- Underneath directory
oth create three three-character files named: rwx ??? *** (Some characters are meta-characters that are special to the shell and will need careful handling. See the Class Notes about Quoting.)
- None of the files have any permissions for user or group.
- File
rwx has full permissions for other. Record the permissions.
- File
??? has no permissions for other. Record the permissions.
- File
*** has only read permission for other. Record the permissions.
Remember to read all the words above about working from top to bottom and then from bottom to top in this Part.
Run the Checking Program to verify your work so far.
Part C – Using umask to mask default permissionsIndex
Use a text editor to create and edit the file umask.txt with this content:
1. drwxrwxrwx is created with a umask 0___
2. drwxrwxr-x is created with a umask 0___
3. drwxr-xr-x is created with a umask 0___
4. drwxr-xr-- is created with a umask 0___
5. drwxr-x--- is created with a umask 0___
6. drwxr----- is created with a umask 0___
7. drwx------ is created with a umask 0___
8. d--x------ is created with a umask 0___
9. d--------- is created with a umask 0___
The file must have a word count of: 9 72 387 umask.txt
Edit the file and replace the three underscores ___ with the correct three-digit umask value that would result in each set of symbolic permissions for a new directory. (Check your work by setting your umask to the above value and then creating and examining the permissions of a new directory.)
The finished file must have the exact above word count. All correct answers will give a file checksum of 61603.
Do not leave your umask set incorrectly after this exercise.
Run the Checking Program to verify your work so far.
Part D – Minimal PermissionsIndex
Copy this text into file minimal.txt and replace all the underscore characters using your answers from Worksheet #08. Missing permissions should be given as dashes so that each set of three underscores is replaced with exactly three other characters:
*** Table of MINIMUM rwx symbolic permissions ***
1. copy a file: srcdir=___ srcfile=___ targetdir=___
2. move a file: srcdir=___ srcfile=___ targetdir=___
3. link to a file: srcdir=___ srcfile=___ targetdir=___
4. delete a file: srcdir=___ srcfile=___
5. read a file: srcdir=___ srcfile=___
6. modify an existing file: dir=___ oldfile=___
7. create a new file: dir=___
- The original file and the edited file must both have 8 lines and 55 words.
- Every set of three underscores must be replaced with three permissions characters, as explained in the Summary of
rwx permissions.
Run the Checking Program to verify your work so far.
When you are doneIndex
That is all the tasks you need to do.
Check your work a final time using the Checking Program and save the output as described below. Submit your mark following the directions below.
Checking, Marking, and Submitting your WorkIndex
Summary: Do some tasks, then run the checking program to verify your work as you go. You can run the checking program as often as you want. When you have the best mark, upload the marks file to Blackboard.
Since I also do manual marking of student assignments, your final mark may not be the same as the mark submitted using the current version of the Checking Program. I do not guarantee that any version of the Checking Program will find all the errors in your work. Complete your assignments according to the specifications, not according to the incomplete set of the mistakes detected by the Checking Program.
There is a Checking Program named assignment10check in the Source Directory on the CLS. Create a Symbolic Link to this program named check under your new assignment10 directory on the CLS so that you can easily run the program to check your work and assign your work a mark on the CLS. Note: You can create a symbolic link to this executable program but you do not have permission to read or copy the program file.
Execute the above “check” program on the CLS using its symbolic link. (Review the Search Path notes if you forget how to run a program by pathname from the command line.) This program will check your fetched CentOS work, assign you a mark, and display the output on your screen. (You may want to paginate the long output so you can read all of it.)
You may run the “check” program as many times as you wish, to correct mistakes and get the best mark. Some task sections require you to finish the whole section before running the checking program at the end; you may not always be able to run the checking program successfully after every single task step.
- When you are done with checking this assignment, and you like what you see on your screen, redirect the output of the Checking Program into the text file
assignment10.txt under your assignment10 directory on the CLS. Use the exact name assignment10.txt in your assignment10 directory. Case (upper/lower case letters) matters. Be absolutely accurate, as if your marks depended on it. Do not edit the file.
- Make sure the file actually contains the output of the checking program!
- The last text line of the file should begin with:
YOUR MARK for
- Really! MAKE SURE THE FILE HAS YOUR MARKS IN IT!
- Transfer the above
assignment10.txt file from the CLS to your local computer and verify that the file still contains all the output from the checking program. Do not edit this file! No empty files, please! Edited or damaged files will not be marked. You may want to refer to your File Transfer notes.
- Make sure the file actually contains the output of the checking program!
- The last text line of the file should begin with:
YOUR MARK for
- Really! MAKE SURE THE FILE HAS YOUR MARKS IN IT!
Upload the assignment10.txt file under the correct Assignment area on Blackboard (with the exact name) before the due date. Upload the file via the assignment10 “Upload Assignment” facility in Blackboard: click on the underlined assignment10 link in Blackboard. Use “Attach File” and “Submit” to upload your plain text file.
No word-processor documents. Do not send email. Use only “Attach File”. Do not enter any text into the Submission or Comments boxes on Blackboard; I do not read them. Use only the “Attach File” section followed by the Submit button. If you need to comment on any assignment submission, send me email.
You can upload the file more than once; I only look at the most recent. You must upload the file with the correct name; you cannot correct the name as you upload it to Blackboard.
- Verify that Blackboard has received your submission: After using the Submit button, you will see a page titled Review Submission History that will show all your submissions.
- Verify that your latest submission has the correct 16-character, lower-case file name beside the Attached Files heading.
- The Submission Field and Student Comments headings must be empty. (I do not read them.)
- Save a screen capture showing the uploaded file name. If there is an upload missing, you will need this to prove that you uploaded the file. (Blackboard has never lost a file.)
You will also see the Review Submission History page any time you already have an assignment attempt uploaded and you click on the underlined assignment10 link.
You cannot delete an assignment attempt, but you can always upload a new version. I only mark the latest version.
Your instructor may also mark files in your directory in your CLS account after the due date. Leave everything there on the CLS. Do not delete any assignment work from the CLS until after the term is over!
I do not accept any assignment submissions by email. Use only the Blackboard Attach File. No word processor documents. Plain Text only.
Use the exact file name given above. Upload only one single file of Linux-format plain text, not HTML, not RTF, not MSWord. No fonts, no word-processing. Linux plain text only.
NO EMAIL, WORD PROCESSOR, PDF, RTF, or HTML DOCUMENTS ACCEPTED.
No marks are awarded for submitting under the wrong assignment number or for using the wrong file name. Use the exact 16-character, lower-case name given above.
WARNING: Some inattentive students don’t read all these words. Don’t make that mistake! Be exact.
READ ALL THE WORDS. OH PLEASE, PLEASE, PLEASE READ ALL THE WORDS!
Author:
| Ian! D. Allen - idallen@idallen.ca - Ottawa, Ontario, Canada
| Home Page: http://idallen.com/ Contact Improv: http://contactimprov.ca/
| College professor (Free/Libre GNU+Linux) at: http://teaching.idallen.com/
| Defend digital freedom: http://eff.org/ and have fun: http://fools.ca/
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