Updated: 2014-03-20 20:17 EDT

1 Due Date and Deliverables

Do not print this assignment on paper!

2 Purpose of this Assignment

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.

  1. Review Remote Login to the Course Linux Server (CLS)
  2. Review basic Linux command line operations and utilities, e.g. from CST8207 GNU/Linux Operating Systems I.

3 Introduction and Overview

This is an overview of how you are expected to complete this assignment. Read all the words before you start working.

  1. Complete the Tasks listed below.
  2. Verify your own work before running the Checking Program.
  3. Run the Checking Program to help you find errors.
  4. Submit the output of the Checking Program to Blackboard before the due date.
  5. READ ALL THE WORDS to work effectively and not waste time.

You will create file system structure in your HOME directory, with various directories, files, and links. 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 tasks 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 these files, directories, and links in place 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; you must have your term work available right until term end.

This is a review lab, and all of the tasks can be completed with knowledge of the material from the prerequisite course CST8207 GNU/Linux Operating Systems I; however, you will probably need to refresh your memory of various topics by referring to the CST8207 course notes and the Linux man pages. Your lab instructor is there to help you, but s/he will want you to have tried consulting the notes and man pages first.

The prevous term’s course notes are available on the Internet here: CST8207 GNU/Linux Operating Systems I. All the notes files are also on the CLS. You can learn about how to read and search these 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.

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.

3.1 The Source Directory

All references to the “Source Directory” below are to the CLS directory ~idallen/cst8177/14w/assignment01/ 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).

4 Tasks

4.1 Set Up

  1. Do a Remote Login to the Course Linux Server (CLS) from any existing computer, using the name appropriate for whether you are on-campus or off-campus. Pay particular attention to the special non-Algonquin password you must use, or else you will lock yourself out of the machine. All work in this assignment must be done on the CLS.

  2. Create the following directory structure in your CLS HOME directory and record (for study purposes) the series of Unix commands you used to create it. Spelling and capitalization must be exactly as shown:

    CST8177-14W
    `-- Assignments
        `-- assignment01

    This directory is the base directory for most pathnames in this assignment. Store your files and answers here.

  3. There is a Checking Program named assignment01check in the Source Directory on the CLS. Follow the instructions in the first two steps at the start of Checking Program to create a working symbolic link to this program.

Check your work so far using the assignment01check program symlink.

4.2 Simple Tasks

  1. From your HOME directory, use the ls command with options to give a long listing (showing permissions), include all hidden files, include inode numbers, and recursively include all subdirectories. (Do not use any other options.) When the output is correct, redirect the output of this command into new file listing_start under assignment01 - it will be at least 16 lines of output. (If you have files from CST8207 in your account, you may get some “permission denied” errors doing the listing [ignore the errors] and the number will be many more than 16 lines.)

  2. Run the whoami command. When the output is correct, redirect the output of this command into new file whoami under assignment01

  3. Run the id command. When the output is correct, append the output of this command to existing file whoami under assignment01. (Note the word append). The file must now have two lines of output in it. Check it!

  4. Rename the file whoami to have the new name whoamiid (in the same directory) and make extra sure you spelled the new name correctly.

  5. Use a command to count only the number of lines (not characters or words) in file read.txt in the Source Directory. (You’ll know you have the right file if the size is 818 characters.) When the output is correct, redirect the output of this command (the output containing only the line count number, not any other numbers) into new file readlines under assignment01

  6. Use a command to search for and display the single line containing the exact text phrase “permissions is useless” located inside any one of the text files (files having a .txt file extension) located in the notes/ directory of the previous term CST8207 (fall 2013). The Introduction and Overview explains where to find these notes and how to search them, just as you did last term. When the output is correct, redirect the one line of output of this command into new file useless under assignment01 The file should be one line long.

Check your work so far using the assignment01check program symlink.

4.3 File Permission Tasks

  1. Copy the binary program file /bin/hostname three times to files named read_only, write_only, and execute_only under your assignment01 directory. This is a BINARY program file, so do not display the content of the file on your terminal screen!

  2. Change the permissions on all three copied files so that group and other have no permissions. (You can do this with one command name and a file GLOB pattern.)

  3. Change the permissions on the read_only file so that only you can read the file but not write or execute the file.
    1. Verify readability of the file by using any command that reads the content of the file. For example, you can word count the file or try to copy the file to /dev/null.
    2. Verify non-writability by attempting to overwrite the file. Attempts to overwrite should fail with “permission denied”.
    3. Verify non-executability by attempting to execute the file as a program. It should fail with “permission denied”. (You may need to review how to execute a file using a pathname. The error must be “permission denied” not “no such file” or “command not found”.)
  4. Change the permissions on the write_only file so that only you can write (including append to) the file but not read or execute the file.
    1. Using operations similar to the previous file, verify that you can write the file but not read or execute it.
  5. Change the permissions on the execute_only file so that only you can execute the file but not read or write the file.
    1. Using operations similar to the previous files, verify that you can execute the file but not read or write it.

Check your work so far using the assignment01check program symlink.

4.4 Directory Permission Tasks

  1. Make the following directory structure under assignment01/

    permissions/
    permissions/read_only/
    permissions/write_only/
    permissions/execute_only/
  2. Change the permissions on the permissions/ directory so the owner (you) can read, write, and search, but group and other have no permissions.

  3. Change the permissions on all three subdirectories of permissions/ so that that group and other have no permissions. (You can do this with one command name and a file GLOB pattern.)

  4. Change the permissions on read_only/ so that you can see the names in the directory (with echo read_only/* or similar), but cannot take an accurate long listing, and cannot create files, and cannot cd into the directory. (Verify that you can/cannot do these things!)

    Hint: Of course echo read_only/* will only show file names if you actually create those files.

  5. Change the permissions on write_only/ so that you cannot see the names in the directory, but you can add new files to the directory, delete files from the directory, and cd into the directory. (Verify that you can/cannot do these things!)

  6. Change the permissions on execute_only/ so that you can (only) cd into the directory. You cannot see the names in the directory or add or delete files from the directory. Verify!

Check your work so far using the assignment01check program symlink.

4.5 Finding files in a maze

  1. Under the Source Directory there is a directory named maze (four letters). This maze contains many hidden sub-directories. Use a single command (no pipes needed) to find in the maze a single hidden file with a basename similar to .abcd0001*txt, but look for the basename that starts with a period followed by your own Blackboard userid, not the fake userid abcd0001. To look for the file, replace the string abcd0001 in .abcd0001*txt with your own userid before you look. The basename you find must be exactly 13 characters long and contain a period and a real asterisk. It must have no leading or trailing blanks around it.

    Hint#1: You might want to use a command that finds files by basename to do this. (Do not try to use “cd” and “ls” to find your file; the maze is really big.)

    Hint#2: If you want to find a name containing a real asterisk, you may need to escape the asterisk to stop it from being used as a pattern character (wildcard), and you need to do this both for the shell that reads your command line and for the command that finds the files. if you get the escaping right, you will find exactly one file.

  2. When you find the right file basename (there is only one for your userid), put its shortest full absolute pathname into new file foundmaze under your assignment01 directory. Note: Shortest absolute pathnames contain no /./ or /../ or tilde (“~”) expressions; simplify the path to the shortest possible absolute pathname.

Check your work so far using the assignment01check program symlink.

4.8 Finishing Tasks

  1. Make a backup copy of your listing_start file, in case you accidentally overwrite it in the next step.

  2. From the same starting directory, repeat the command you used to create listing_start at the beginning of this lab, but redirect the output this time into the file listing_end in the same directory as listing_start, and make sure that all errors (standard error output) also go into the output file and not on the screen. (You might find your shell history useful here. There is a special syntax to also redirect error messages.)

  3. Use the diff command to compare the earlier listing file to the previous one you did before starting this lab. Note the many changes!

4.9 When you are done

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.

5 Checking, Marking, and Submitting your Work

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.

  1. There is a Checking Program named assignment01check in the Source Directory on the CLS. Create a Symbolic Link to this program named check under your new assignment01 directory so that you can easily run the program to check your work and assign your work a mark. Note: You can create a symbolic link to this executable program but you do not have permission to read or copy the program file.

  2. Execute the above “check” program using its new 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 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.

  3. 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 assignment01.txt under your assignment01 directory. Use the exact name assignment01.txt in your assignment01 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!

  4. Transfer the above assignment01.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.

  5. Submit the assignment01.txt file under the correct Assignment area on Blackboard (with the exact name) before the due date. Upload the file via the assignment01 “Upload Assignment” facility in Blackboard: click on the underlined assignment01 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 want to send me comments about your assignment, use email.)

  6. Your instructor may also mark the assignment01 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!

Use the exact file name given above. Upload only one single file of plain text, not HTML, not MSWord. No fonts, no word-processing. Plain text only.

Did I mention that the format is plain text (suitable for VIM/Nano/Pico/Gedit or Notepad)?

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 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: 
| Todd Kelly and
| 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/

Plain Text - plain text version of this page in Pandoc Markdown format


Campaign for non-browser-specific HTML   Valid XHTML 1.0 Transitional   Valid CSS!   Creative Commons by nc sa 3.0   Hacker Ideals Emblem   Author Ian! D. Allen