umask
, web site imageWinter 2019 - January to April 2019 - Updated 2019-04-02 15:19 EDT
Do not print this assignment on paper!
- On paper, you will miss updates, corrections, and hints added to the online version.
- On paper, you cannot follow any of the hyperlink URLs that lead you to hints and course notes relevant to answering a question.
- On paper, scrolling text boxes will be cut off and not print properly.
23h59 (11:59pm) Sunday April 7, 2019 (end of Week 12)
WARNING: Some inattentive students upload Assignment #09 into the Assignment #08 upload area. Don’t make that mistake! Be exact.
This assignment is based on your weekly Class Notes and covers these topics:
As noted above in the Prerequisites, parts of this assignment come from your answers in Worksheet #08 PDF.
For full marks, follow these directions exactly:
These tasks must be done in your account via Remote Login to the Course Linux Server.
Do the tasks in order, from top to bottom. Do not skip steps. Most tasks are independent, but some depend on successful completion of a previous task.
READ ALL THE WORDS in each task before you begin the task, especially all the Hints, Notes, and links.
Verify your own work before running the Checking Program. You won’t have a Checking Program at your job interview and the Checking Program is not guaranteed to check everything.
Run the Checking Program at the end of the task to grade your work and help you find some of your errors. A perfect mark from the Checking Program does not mean your answers are correct.
When you are done with this Assignment, submit the output of the Checking Program to Brightspace before the due date, following the directions given at the end of this Assignment.
You can use the Checking Program to check your work after you have completed each task.
Most task sections below require you to finish the whole task section before running the Checking Program. You may not always be able to run the Checking Program successfully in the middle of a task or after every single task sub-step. The assignment tells you where you can safely check your work.
You will create file system structure in your CLS home directory containing various directories and files. When you are finished the tasks, leave the files and directories in place on the CLS as part of your deliverables for your instructor to verify.
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. Do not delete any assignment work until after the term is over!
You can modify your work and check it with the Checking Program as often as you like before you submit your final mark to Brightspace. You can upload your marks to Brightspace as many times as you like before the due date. Partial marks are accepted.
Your instructor will also 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 after you have submitted your final mark to Brightspace.
You must keep a list of command names used each week and write down what each command does, as described in the List of Commands You Should Know. Without that list to remind you what command names to use, you will find future assignments very difficult.
All course notes are available on the Internet and also on the CLS. You can learn about how to read and search these CLS files using the command line on the CLS under the heading Copies of the CST8207 course notes near the bottom of the page Course Linux Server. You also learned how to search the notes in Assignment #05 HTML.
All references to the Source Directory below are to the CLS directory
~idallen/cst8207/19w/assignment09/
and that name starts with a
tilde character ~
followed by a user name 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.
Have you completed all the prerequisites, before attempting these tasks?
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. All work in this assignment must be done on the CLS.
Create the assignment09
directory in your usual Assignments
directory.
This assignment09
directory is called the Base Directory for most
pathnames in this assignment. Store your files and answers in this
Base Directory, not in your HOME directory or anywhere else.
check
check
symbolic link needed to run the Checking
Program, as you did in your last assignment and as described in
the section Checking Program below.Hints: See your previous assignment for hints on doing the above.
Use the symbolic link to run the Checking Program to verify your work so far.
You need to understand Permissions for this task.
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 in the next Part below, or you can record all of the permissions after you have finished the Part below, before you run the Checking Program.
You will need to complete the next Part, below, before you can finish recording all the permissions in this Part. The two Parts go together.
abcd0001.txt
Copy the file Record.txt
from the Source Directory into your own file
abcd0001
.txt
(no spaces) where the
text abcd0001
userid is replaced by your own eight-character
userid in the file name. This file copy should be located directly
under your Base Directory.
Fix the permissions on the file so that you can edit it and nobody else (group or other) has any permissions at all.
Note on the verb edit: To edit a file, you need to be able to read the contents of the file, change the contents, and write them back into the file. You do not need to execute the contents of the file unless you are editing a script file.
You will need to edit your copy of the file with a Linux command-line text editor. The VI Text Editor is recommended, since that is the universal text editor for system administrators.
abcd0001.txt
file you just created and replace the
entire KEY:
line in the file with the output of running the Checking
Program with a first argument of -s
and a second argument that
is the basename
of the file you are editing, i.e. abcd0001.txt
Hints on replacing the
KEY:
line in the file:
First, run the Checking Program with the correct first and second arguments: The first argument is
-s
and the second argument is yourabcd0001.txt
basename file name. (Use your own userid in the name, notabcd0001
.) The correctKEY:
output will be 1 line, 3 words, and approximately 88 characters including the newline. The correct output looks similar to this:
KEY:
abcd0001.txt =8/V3ETL3AjM4Q1UD9/MwATM/L2NwIDO0N3Y/THe05iY3AjM4Q3cj9vNyczN1YzN4QTMM
Edit the new
KEY:
line into theabcd0001.txt
file, replacing just theKEY:
line that is already in that file. Edit theabcd0001.txt
file and replace theKEY:
line in that file with your newKEY:
line. You can do this many ways:
- You could append the new
KEY:
line to the bottom of theabcd0001.txt
file and then edit the file to delete the oldKEY:
line and replace it with the new one that you appended to the bottom of the file. (You did this line moving in VIMvimtutor
Lesson 3.1. THE PUT COMMAND.)- You could put the new
KEY:
output into a temporary file, and then edit theabcd0001.txt
file and read in that temporary file. (You did this in VIMvimtutor
Lesson 5.4. RETRIEVING AND MERGING FILES.)- You could also replace just the
KEY:
line using the VIM!!
method from section 2.1 #10 in Worksheet #06 PDF. (This is my favourite method; this is how I would do it.)- You could use your terminal to copy-and-paste the new
KEY:
line into your editor, replacing just the oldKEY:
line in the file.
Run the Checking Program to verify your work so far.
_
__
in
the file with the correct three-digit numeric (octal) permission
value that you use in the next Part below.Be careful not to make other accidental changes to 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.
diff
between the original and your
edited version may be helpful in knowing what you changed.cmp -bl ~idallen/cst8207/19w/assignment09/Record.txt abcd0001.txt
40
in the cmp
output.12
(^J
) in the cmp
output.man ascii
for a full table of octal character values.You need to understand Permissions for this task. Do the permissions section of Worksheet #08 PDF 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, after you have created all the structure.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 this set of directories and files, and set the permissions as given. Make sure you create directories where directories are required and files where files are required.
head
head
under your Base Directory:
head
allows the group to use ls
to see the content,
but the group cannot create files or cd
into the directory.
The user has full permissions. Others have permission to access
files if they know their names, but no permission to see or change
the names. Record the permissions for head
in the Record file.Ooo Aaa Bbb
head
create three three-letter directories named:
Ooo Aaa Bbb
Ooo
has no permissions for user or group. Others have full
permissions. Record the permissions.Aaa
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.Bbb
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.ab ac ad
Aaa
create three two-letter files named:
ab ac ad
ab
has execute permission (only) for the user.
Record the permissions.ac
has read permission (only) for the user.
Record the permissions.ad
has write permission (only) for the user.
Record the permissions.ba bb bc
Bbb
create three two-letter files named:
ba bb bc
ba
has read and execute permission (only) for the group. Record
the permissions.bb
has read and write permission (only) for the group. Record
the permissions.bc
has write and execute permission (only) for the group. Record
the permissions.bbb *** ???
Ooo
create three three-character files named:
bbb *** ???
(Some characters are meta-characters that are special to the shell
and will need careful handling. Review Quoting.)
bbb
has full permissions for other. Record the permissions.***
has only write permission for other. Record the permissions.???
has no permissions 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.
You need to understand Permissions for this task. Do the permissions section of Worksheet #08 PDF before continuing. Record all your answers for later quizzes.
MinPerms.txt
Copy the file MinPerms.txt
from the Source Directory into your
Base Directory.
Fix the permissions on the file so that only you and your group can edit it. (See the Hints about the edit verb in Part A.)
Edit the file you just created and replace the entire KEY:
line in
the file with the output of running the Checking Program
with a first argument of -s
and a second argument that is the
basename of the file
you are editing, i.e. MinPerms.txt
(To do this, review the KEY:
Hints from Part A.)
Run the Checking Program to verify your work so far.
_
__
with your answers from Worksheet #08 PDF.
Missing permissions should be given as dashes so that each set of
three underscores is replaced with exactly three other characters,
e.g. replace _
__
with -w-
not with -w
or w
.Be careful not to make other accidental changes to 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.
rwx
permissions.diff
between the original and your
edited version may be helpful in knowing what you changed.cmp -bl ~idallen/cst8207/19w/assignment09/MinPerms.txt MinPerms.txt
40
in the cmp
output.12
(^J
) in the cmp
output.man ascii
for a full table of octal character values.Run the Checking Program to verify your work so far.
umask
to mask default permissionsIndexYou need to understand Umask for this task. Do the umask
section of
Worksheet #08 PDF before continuing. Record all your answers for
later quizzes.
UmaskFil.txt
Copy the file UmaskFil.txt
from the Source Directory into your
Base Directory.
Fix the permissions on the file so that you can edit it and your group and others can only read it.
Edit the file you just created and replace the entire KEY:
line in
the file with the output of running the Checking Program
with a first argument of -s
and a second argument that is the
basename of the file
you are editing, i.e. UmaskFil.txt
(To do this, review the KEY:
Hints from Part A.)
Run the Checking Program to verify your work so far.
_
__
with the correct three-digit umask
value that
would result in each set of symbolic permissions for a new directory.
(Optionally check your work by setting your umask
to the above value
and then creating and examining the permissions of a new directory.)Be careful not to make other accidental changes to 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.
diff
between the original and your
edited version may be helpful in knowing what you changed.cmp -bl ~idallen/cst8207/19w/assignment09/UmaskFil.txt UmaskFil.txt
40
in the cmp
output.12
(^J
) in the cmp
output.man ascii
for a full table of octal character values.umask
set incorrectly after this exercise.Run the Checking Program to verify your work so far.
public_html
index.html
me.jpg
Create a web page and upload your picture, following and Reading All The Words in the directions in the page Student Web Site and Picture.
When you are done, make sure you’ve noted these things:
me.jpg
in your public_html
directory.index.html
index file from the current term..htaccess
file,
then you must allow access from localhost 127.
so that your
instructor can test your web site.Follow the given directions for the size and dimensions of the image file.
If you use optional Access Controls, make sure that your web site is
accessible to 127.
(localhost).
Run the Checking Program to verify your work so far.
That is all the tasks you need to do.
Read your CLS Linux EMail and remove any messages that may be waiting. See EMail on the CLS for help.
Check your work a final time using the Checking Program below and save the standard output of that program into a file as described below. Submit that file (and only that one file) to Brightspace following the directions below.
Your instructor will also mark the Base Directory in your account on the due date. Leave everything there on the CLS. Do not delete anything.
When you are done, log out of the CLS before you close your laptop
or close the PuTTY window, by using the shell exit
command:
$ exit
Nothing seriously bad will happen if you forget to log out, but you may
leave behind an empty, “ghost” login session that may take some days
to time out and disappear. Always exit
before you close your laptop,
PuTTY, or Terminal session.
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 single file that is the output of the Checking Program to Brightspace.
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.
check
There is a Checking Program named assignment09check
in the
Source Directory on the CLS. Create a symbolic link named check
in your Base Directory that links to the above Checking Program
in the Source Directory, as you did in a previous assignment.
Execute the above Checking Program as a command line on the CLS. The checking program will check your work, assign you a mark, and display the output on your screen:
$ ./check | less
You may run the Checking Program as many times as you wish, allowing you to correct mistakes and get the best assignment 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 this assignment, and you like the mark
displayed on your screen by the Checking Program, you must
redirect only the standard output of the Checking Program
into the text file assignment09.txt
in your Base Directory on the
CLS, like this:
$ ./check >assignment09.txt
assignment09.txt
file name.You can view the output file one-page-at-a-time using the less
program (use the space bar to page forward and use the letter q
to quit):
$ less assignment09.txt
less
use the space bar to page forward and use the letter q
to quit).YOUR MARK for
Transfer the above single file assignment09.txt
(containing the
output from the Checking Program) from the CLS Base Directory
to your local computer.
YOUR MARK for
Upload the single assignment09.txt
file from your local computer to the
correct A-09 Assignment #09 area on Brightspace before the due date:
assignment09.txt
name.
Do not use any of the names from Assignment 1.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!
Notes:
I do not accept any assignment submissions by EMail. Use only the Brightspace Upload and Submit method.
Use the exact file name given above. Upload only one single file of output from the Checking Program.
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 The Words. Don’t make that mistake! Be exact.
READ ALL THE WORDS. OH PLEASE, PLEASE, PLEASE READ ALL THE WORDS!