3.1 The Source DirectoryIndex

All references to the “Source Directory” below are to the CLS directory ~idallen/cst8207/13f/assignment02/ 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).

4.1 Worksheet and PromptIndex

These worksheets prepare you to do the numbered tasks listed below by executing commands via Remote Login to the Course Linux Server.

You can download Libre Office (or Open Office) for Windows to edit the Worksheet *.odt files and save your answers. (Or you can print the PDF and write your answers on paper.) Do not use MSWord.

Record and save all your worksheet answers for study and quizzes!

1. Use LibreOffice or OpenOffice to open, complete, and save: Lab Worksheet #02 ODT
   • Do not use MSWord to open this file; it damages the file.
   • You must read the week’s Class Notes before you do the worksheet.
   • You will find it easier to write over the red underscores using “OVERWRITE” typing mode instead of the default “INSERT” mode.
   • Another way to fill in answers is to double-click to select the entire line of underscores and then simply type or paste to replace it.
   • Record and save all your worksheet answers for study and quizzes!
   • Read All The Words
2. Use LibreOffice or OpenOffice to open, complete, and save: Lab Worksheet #03 ODT
   • See the notes above for the previous worksheet.
3. Using the PS1 variable syntax shown in Lab Worksheet #02 HTML, set your prompt to include your user name, your computer name, and the basename of your current working directory. (See the definition of basename in the Pathnames class notes.)
   • Your prompt should look similar to this:   [abcd0001@idallen-ubuntu ~]$
   Set your prompt every time you log in to the CLS, so that the prompt changes to tell you you the basename of your current working directory. This is faster than typing pwd all the time!

4.2 Security – Change your CLS passwordIndex

The CLS is on the public Internet; security is important. Choose your password carefully. Accounts that do not have their passwords changed before the due date of this assignment will be disabled.

4. Read on Wikipedia: Guidelines for strong passwords

5. Read this XKCD comic on good passwords

6. Now RTFM for the Unix command named passwd (note the odd spelling). No arguments or options are needed to this command to change your own password. The passwd command is also described in Lab Worksheet #02 HTML.

7. Change your CLS password to one that is more secure than the one you were given. Find a way to remember your new password. If you forget your password, contact your Linux instructor to have it reset.

4.3 Creating new directories and filesIndex

8. 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:

   CST8207-13F
   `-- Assignments
       `-- assignment02
           `-- tree
               |-- one
               |   `-- oneone
               `-- two
                   `-- twotwo

   • The CST8207-13F directory is created in your CLS HOME directory.
     • The Assignments directory is created in the CST8207-13F directory.
       • The assignment02 directory is created in the Assignments directory.
         • The tree directory is created in the assignment02 directory.
           • Under tree are two new directories named one and two (three letters each).
             • Under directory one is new directory oneone (six letters).
             • Under directory two is new directory twotwo (six letters).

   Note: You can create the entire directory tree above using one single command with one option and two pathname arguments. System administrators like to work efficiently – they learn how to do things quickly.

   You can check your work by making your HOME directory your current directory and using one of these tree commands below. Use the command that gives the best-looking output:

   $ tree CST8207-13F
   $ tree -A CST8207-13F

   The correct output will be similar to the ASCII tree diagram above. The spelling and capitalization must be exactly as shown.

9. Make the assignment02 directory your current directory and then use a command to recursively generate a list of all pathnames under your tree directory. (You used this recursive command this at the end of Lab Worksheet #02 HTML. Do not use the tree command.) The recursive output of all pathnames under your tree directory will be exactly five lines long and will contain this exact line in the output somewhere (along with another four lines):

   tree/one/oneone

   Make sure the exact line above appears as one of the five lines!

Recall that you can redirect any output that appears on your screen into a file by adding to the end of the command line a “greater than” angle bracket (>) followed by a file name. (We did this using the cal command to create the cal.txt file in the Week 1 lab.)

10. When the five lines of recursive output above on your screen looks correct, redirect the output of the command into the file named paths.txt in the oneone directory that you created earlier. (Use a relative path down to the oneone directory, as shown in the lectures.)

11. Make the oneone directory your current directory. Use a command to list the files in the current directory to confirm that the paths.txt file is here. Use another command to display the contents of the paths.txt file, and make sure it contains at least five lines of pathnames.

12. Copy the paths.txt file (from the current oneone directory) into the twotwo directory that you created earlier, giving it the new name paths.txt.copy as you copy it. Again, use relative paths to do the copy, as shown in the lectures. (Hint: Draw a file system hierarchy picture to help you derive the correct relative pathname.)

Run the Checking Program to verify your work so far.

4.4 Working with existing directories and filesIndex

13. Execute this exact command line in your account on the CLS:

    $ ~idallen/cst8207/13f/assignment02/create

• There is a leading tilde character ~ directly in front of the account name idallen, indicating to the shell that the pathname starts with the HOME directory of idallen (seven letters).

• The command will create a directory named stuff in your assignment02 directory. It will contain some sub-directories and files. Verify that stuff has been created.

• You can re-execute the above line to start over from scratch, if you make errors in this part of the assignment.

• To know what files and directories have been created by the above command line, use a command that will recursively show all the files and directories under a starting directory. (You already used this command, above.)

All the following commands in this section apply to files and directories under the new stuff directory. You will have to use commands to find some of the file names mentioned here; they may be located under sub-directories. (See Searching and Finding Files.) Some of these tasks may require more than one command to complete.

14. Find and read the file named README.txt (located somewhere under stuff). You have to find this file.

15. Read and then delete the file foo.txt that is in the same directory as the README.txt file. (Do not delete any other decoy files named foo.txt that may be in different directories.)

16. Move (rename) the file dst to be dst.bak (This is a move, not a copy. It renames the file.)

17. Directly under the stuff directory, create a new empty directory named dst (three letters). (Make sure you create dst under stuff, not in your HOME or any other directory.)

18. Find the file named services (not the directory with the same name) and move (rename) that services file to be named ports under the new directory dst that you just created. (This is a move/rename, not a copy.) Make sure you move the file, not the directory with the same name.

Run the Checking Program to verify your work so far.

4.5 Finding files in a mazeIndex

19. Under the Source Directory there is a directory named maze (four letters). This maze contains many hidden sub-directories. (You need a special option to see hidden files and directories.) In this maze, use a single command to recursively find the file with a 12-character basename that looks similar to abcd0001.txt but where the eight-character abcd0001 part of the name is replaced by your own account userid. You must use a single command that finds files by basename to find this 12-character file name. Do not try to use cd and ls to find the file in the maze; the maze is very big. (You have previously used the command you will need here.)

20. When you have found your personal abcd0001.txt file in the maze, copy your file into the dst directory you created above, using the new name me.txt under your dst directory. Read the file to make sure it’s the right one after you copy it into the dst directory.

Run the Checking Program to verify your work so far.

That is all the tasks you need to do. Next, mark your work: