3.1 The Source DirectoryIndex

All references to the “Source Directory” below are to the CLS directory ~idallen/cst8207/14w/assignment06/ 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.

4.1 Set Up – The Base DirectoryIndex

1. Create the following directory structure starting in your CLS HOME directory and record (for study purposes) the series of Unix commands you used to create it. (You do not have to create any directories that you have already created in a previous assignment.) Spelling and capitalization must be exactly as shown:
   1. Create the CST8207-14W directory in your CLS HOME directory.
   2. Create the Assignments directory in the CST8207-14W directory.
   3. Create the assignment06 directory in the Assignments directory.

The correct directory tree will look similar to the ASCII tree diagram below. The spelling and capitalization must be exactly as shown.

CST8207-14W
`-- Assignments
    `-- assignment06

This assignment06 directory is the base directory for most pathnames in this assignment. Store your files and answers below in this base assignment06 directory.

Run the Checking Program to verify your work so far.

4.2 Creating Shell Start-Up FilesIndex

1. Review the Class Notes:
   • Shell Variables
   • Start-Up Files

2. Use a Linux text editor to create your .bash_profile and .bashrc files with the minimum suggested content described in the page Start-Up Files. (Your .bash_profile must contain only one line. Your .bashrc must contain at least two lines.)

   Do not set any options or aliases in your .bashrc that you do not understand! If you don’t know the meaning of a setting, don’t use it. You can RTFM in the bash man page for all BASH settings, and RTFM in command man pages to learn about options to commands.

   I will be spot-checking your knowledge of your aliases. Students using aliases they don’t understand will experience much confusion trying to do future assignments. Only use aliases you understand.

   Using the PS1 variable from Worksheet #2 HTML, set your prompt to include your user name, your computer name, and the basename of your current working directory. Put this setting in your .bashrc file.

3. Verify that nothing prints on your screen after you enter your password when you run the non-interactive shell connection using ssh localhost true (as described in the section on Non-interactive shells and PS1:

   $ ssh localhost true
   *** COURSE LINUX SERVER ***
   user@localhost's password:
   $

   For non-interactive commands to work properly, there must be no output on your screen after you enter your password using the above non-interactive command line using the true command.

Your instructor will mark the .bashrc and .bash_profile files in your account on the assignment due date. Do not upload them to Blackboard. Leave them there on the CLS. Do not delete anything.

Run the Checking Program to verify your work so far.

4.3 Working with directories and filesIndex

1. Make a copy of the base3 directory from Assignment #04 into the base directory of this assignment using the name basecopy here. Remember to preserve file attributes when you copy.

2. Rename all the directories by changing every occurrence of bdir to just dir in every pathname, e.g. basecopy/bdir2/bdir2-1/MT2-1 becomes basecopy/dir2/dir2-1/MT2-1.

3. Make basecopy your current directory and redirect the ten lines of recursive find output into the file named basecopyfind.txt in your base directory (not in the current directory). The word count of this file must be: 10 10 112

Run the Checking Program to verify your work so far.

4.4 Finding multiple files in a maze using a GLOB patternIndex

1. Under the Source Directory there is a name maze that is a symbolic link that leads to the same directory maze used in a previous assignment: Assignment #04 HTML.

   In the maze use a single command (not a pipeline) to recursively find all pathnames with a basename that begins with your eight-character userid at the start of the name. For example, if your userid were abcd0001 then you might output pathnames containing basenames such as abcd0001 and abcd0001YYY but not XXXabcd0001 or XXXabcd0001YYY where XXX and YYY can be anything (zero or more characters). You will find exactly 15 pathnames.

2. Modify the same single command you used to find the names above and instead use the option that makes the command show the full information about the names (including permissions, owner, size, date, etc.) instead of just the pathname. You will know you have the right option if the output of the command shows 15 lines and 168 words.

3. Pipe the pathname output of the above command (15 lines of output) into a sorting program and put the reverse-sorted output into file mazefoundreverse.txt under your base directory. The reverse-sorted file will still contain 15 lines and 168 words.

Run the Checking Program to verify your work so far.

4.5 Finding information in the course notesIndex

1. Use the options to fgrep that ignore case and “show files with matches” (RTFM) and find the 23 file names that contain the exact string symbolic link in all the files ending in .txt in the previous term course notes. Exactly 23 file names will print, and one of the pathnames will end in basename 750_booting_and_grub.txt. Hint: Use the oldnotes symbolic link from Assignment #04 and a GLOB pattern that matches all the .txt files under it, using the fgrep method described in Copies of the CST8207 Course Notes.

2. Now redirect the 23 names into file symlinkfound.txt under your base directory. The file must contain 23 lines ending in the .txt suffix.

Run the Checking Program to verify your work so far.

4.6 Scanning the Log FileIndex

1. Use a two-command pipeline to find every line containing the string new denied hosts that appears in January in the denyhosts log file. (This log file is in the same directory as the auth.log file used in class.) You should find 188 matching lines in the file. (Hint: See your class notes from Week 05 Notes. How do you know which lines in the denyhosts file were created in January?)

2. Add one more command to the pipeline (making a total of three commands) to extract only the blank-separated field containing the IP address from each of the above 188 matching lines. (Hint: See your class notes from Week 05 Notes.) The first line (of
   188. will be ['50.46.204.2'] and the last line (of 188) will be ['222.186.62.56'].

3. Put a copy of the three-command pipeline into file denygrep.sh in the base directory. (Put the command pipeline in the file, not the output of the command.) If you execute sh ./denygrep.sh the output should word count as 188 lines and 188 words, with either 3372 or 3373 characters (depending on how you extracted the IP address field).

Run the Checking Program to verify your work so far.

4.7 Using shell environment variablesIndex

Follow correct double-quoting procedures when expanding variables, as noted in Shell Variables.

1. Display the value of the environment variable containing your userid. Put the command you use to do this into file env.sh in the base directory. (Put in the command, not the output.) The file will contain one command line.

2. Display the value of the environment variable containing your home directory. Append the command you use to do this to file env.sh in the base directory. (Put in the command, not the output.) The file will contain two command lines.

3. Display the value of the environment variable containing your assigned shell. Append the command you use to do this to file env.sh in the base directory. (Put in the command, not the output.) The file will contain three command lines.

4. Display the value of the environment variable containing your shell search path. Append the command you use to do this to file env.sh in the base directory. (Put in the command, not the output.) The file will contain four command lines.

5. Run sh ./env.sh and the values of all four environment variables should display on your screen.

Run the Checking Program to verify your work so far.

4.8 Quoting Exercise – Easy VersionIndex

1. Make the above assignment06 base directory your current directory.

2. Copy the script file quotes.sh from the Source Directory into the current directory.

3. Execute this file (enable execute permissions and then run it) or use bash to read the file so that all the commands inside it execute:

   $ chmod ugo+x quotes.sh
   $ ./quotes.sh
   ** - OR USE BASH: - **
   $ bash ./quotes.sh

4. Note that the output of running the script generates an error message and doesn’t match what is written in the script file. (For example: many quotes are missing, GLOB characters and variables are expanding, and the spacing of the words is different.)

   Fix the Quoting inside the file so that every line is fully quoted to appear exactly as written in the file, blanks included, with no meta-character expansion by the shell. The correct output should give eight lines and look exactly like this when you are finished (including all the extra spaces between some of the words):

   Where is the question mark after the file /etc/group?
   Is one also missing after /etc/passwd?
   The shell prompt is contained in the  $PS1  variable.
   This line isn't appearing on my screen properly.  It's missing the quotes.
   This line is also "missing" all the quotes.  It is not "right" yet.
   This is also "missing" all quotes.  It's output that doesn't make sense.
   This isn't working either.  The shell gives an error message.
   ***  This is a file to practice shell quoting.  Do you see this line?  ***

   You must edit the file to make the entire line of text on each line one single shell argument to echo. You can check your success by temporarily substituting the argv.sh program from the Class Notes for the echo command. (You have to put the argv.sh program into the same directory as quotes.sh under the name argv.sh and make it executable. Read the quotes.sh file for details on using an alias inside the quotes file to run this program. Remember to return the script to using only echo after you finish your testing.)

   You’ll know you got it mostly right when you see this wc and sum output (but you’ll need to verify one-argument-per-echo using the argv.sh program):

   $ ./quotes.sh | wc
   8 86 500
   $ ./quotes.sh | sum
   39574   1

   If your line and word count is correct but the number of characters is less, you probably failed to make the entire text one argument to echo on each line. You must use Quoting to hide all the blanks and special characters from the shell on each of the lines. The argv.sh program will tell you if you got it right.

5. When the edited script output is correct, run the script and redirect the script output into file quotesout.txt

Run the Checking Program to verify your work so far.

4.9 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.