Updated: 2017-01-20 00:52 EST

1 Due Date and Deliverables

Do not print this assignment on paper!

WARNING: Some inattentive students upload Assignment #5 into the Assignment #4 upload area. Don’t make that mistake! Be exact.

2 Purpose and Background

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

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 and covers these topics:

For full marks, follow these directions exactly:

  1. Complete the Tasks listed below.
  2. Verify your own work before running the Checking Program. (You won’t have a checking program at your job interview.)
  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 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. The assignment tells you where you can check your work.

When you are finished the tasks, leave the files and directories in place on 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.

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.

2.1 Prerequisites: Do Worksheet 4 and Worksheet 5

You must complete the two Worksheets before attempting this assignment. The worksheets depend on the Readings in the weekly course notes, especially Shell GLOB Patterns and Redirection and Pipes.

See your previous assignments for how best to fill in the worksheets.

These worksheets prepare you to do the rest of the tasks listed below. Failure to complete the worksheets will make the rest of this assignment very difficult. Do the worksheets first!

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

  1. Do a Remote Login to the Course Linux Server (CLS). All work in this assignment must be done on the CLS.

  2. Set your PS1 shell prompt.

  3. Use LibreOffice or OpenOffice to complete Worksheet #04 ODT. (View online: Worksheet #04 HTML.)

  4. Use LibreOffice or OpenOffice to complete Worksheet #05 ODT. (View online: Worksheet #05 HTML.)

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

3 The Source Directory

All references to the Source Directory below are to the CLS directory ~idallen/cst8207/16f/assignment05/ 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.

3.1 Searching the course notes on the CLS

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.

4 Tasks

4.1 Log in to the Course Linux Server

  1. Do a Remote Login to the Course Linux Server (CLS). All work in this assignment must be done on the CLS.

4.2 Set your PS1 Shell Prompt

  1. Using the PS1 variable syntax shown in Section 2 of Worksheet #02 HTML, set your shell 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 shell prompt should look similar to this:   [abcd0001@idallen-ubuntu ~]$

Set your PS1 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! You will learn later how to create a .bashrc file to make this happen automatically every time you log in to the CLS.

Tip Feature: If you use \w instead of \W in the PS1 prompt string, the shell will display the full absolute path of your current working directory instead of just the basename. You may or may not like this feature; it doesn’t leave much room on the command line to type commands without having the command line wrap around to the next line. You choose.

4.3 Set Up – The Base Directory on the CLS

As mentioned in List of Commands You Should Know, you must keep a list of command names used each week and write down what each command does. Without that list to remind you of what command names to use, you will find assignments very difficult.

  1. Create the following directory structure in your CLS personal 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 CST8207-16F directory in your CLS HOME directory.
    2. Create the Assignments directory in the CST8207-16F directory.
    3. Create the assignment05 directory in the Assignments directory.

Hints: See your previous assignment for hints on doing the above.

This assignment05 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.

Run the Checking Program to verify your work so far.

4.4 Using shell GLOB patterns to select names

You need to understand Shell GLOB Patterns to do this task.

  1. Make your HOME directory your current directory.

oldnotes newnotes

  1. In your HOME directory, create two symbolic links to the old and new course notes for CST8207 using the ln -s command and option and the method described in Copies of the CST8207 Course Notes. (The old notes must be term 16w and the new notes must be term 16f in the pathnames you use.)

  2. Do a long listing of the new oldnotes symlink and verify that it looks similar to this (but the userid and time will differ):

    lrwxrwxrwx 1 abcd0001 abcd0001 52 Oct  4 00:00 oldnotes -> /home/idallen/public_html/teaching/cst8207/16w/notes

    You should be able to do ls oldnotes | less and see all the course notes file names from last term (16w). If not, remove and redo the symlink.

  3. In your HOME directory, use the ls command with no options and a single shell GLOB pattern to match all pathnames under the symbolic link oldnotes/ that end in .txt and display all the names on your screen. The shell will find 89 pathnames ending in .txt, and the ls command will display those 89 names on your screen. One of the last names on your screen should look exactly like this:

    oldnotes/worksheet08.txt

    Make sure you see 89 pathnames. (You can use a command pipeline to count the lines and words to be sure you have 89.)

    Hints: No pipeline or find commmand is required to generate the 89 pathnames, just use the ls command with no options and one single GLOB pattern argument starting with the symlink oldnotes/. This use of a GLOB pattern on a command line is illustrated in Copies of the CST8207 Course Notes. The example in the notes uses the given GLOB pattern to generate pathnames to the ls command and count them. Follow the example and display the 89 pathnames on your screen instead of counting them. (Don’t use any redirection.)

oldfound.txt

  1. When the ls output on your screen is correct (89 names), redirect the output 89 names into file oldfound.txt under your Base Directory (not under your current HOME directory). The file must contain 89 names, one per line.

    Note: The ls command will put each name on a separate line when output is not being sent to your screen.

  2. Still in your HOME directory, use the echo command with a shell GLOB pattern to match all pathnames under oldnotes/ that contain the acronym RTFM anywhere in the file name and display the names on your screen. The shell will find two pathnames, one ending in .html and the other in .txt, and the echo command will display those two names on your screen on one line.

    Hints: See the previous Hint. Use only a GLOB pattern.

foundman.txt

  1. When the echo output on your screen is correct (two names on one line), redirect the output into file foundman.txt under your Base Directory (not under your current HOME directory). The file must contain two names on one line.

  2. Again in your HOME directory, use the echo command with a shell GLOB pattern to match pathnames under oldnotes/ that contain the digit 2 anywhere in the file name and end in the extension .pdf at the end. The shell will find five pathnames, each ending in .pdf at the end, and the echo command will display those five names on your screen on one (long) line.

  3. When the echo output on your screen is correct (five names on one long line), change the command name from echo to ls and add an option to show the full, long information about the pathnames. You should see five lines on your screen, showing the full file information for each of the five files. One of the lines should look like this:

    -rw-r--r-- 2 idallen idallen  25791 Jul  7  2015 oldnotes/2015-2016_CST8207.pdf

foundpdf.txt

  1. Now redirect the five lines of long output on your screen into file foundpdf.txt under your Base Directory (not under your current HOME directory). The file must contain five lines and approximately 45 words.

Run the Checking Program to verify your work so far.

4.5 Searching for text inside files (e.g. course notes)

As mentioned in Worksheet #03 HTML, you can choose which text search command you use depending on whether special characters are being used in the search string. You should always use the fixed-string fgrep command to begin with in this introductory course. You will learn regular expressions and the grep command later in the term. Use fgrep for this assignment.

Always verify that the correct output appears on your screen before you redirect the output into a file. You can only redirect what you can see.

Make your Base Directory your current directory for this section.

myaccount.txt

  1. Search for lines containing your login userid in the password file. You should find exactly one line. (For an explanation of what the seven fields are in this line, see man 5 passwd.

  2. When the output is correct (one line) then redirect the output into file myaccount.txt in your Base Directory. The file should contain one line.

  3. Search for lines containing a period (dot) character (.) in the file special.txt in the Source Directory.

    Hint: A period can be a special character. Choose the right text searching command, as described at the start of this section. The word count of the six lines of correct output should be: 6 44 241

dotlines.txt

  1. When you have the correct output on your screen, redirect that output into file dotlines.txt under your Base Directory. The word count of the file should be the same as above (six lines).

  2. Search for lines containing two adjacent asterisk characters (**) in the file special.txt in the Source Directory.

    Hint: An asterisk is a special character to the shell. Hide the asterisks so that the shell does not GLOB expand them. Also choose the right text searching command, as described at the start of this section. The word count of the four lines of correct output should be: 4 37 209

starlines.txt

  1. When you have the correct output on your screen, redirect that output into file starlines.txt under your Base Directory. The word count of the file should be the same as above (four lines).

  2. In your Base Directory, create two more symbolic links to the old and new course notes for CST8207, as you did inside your HOME directory earlier in this assignment.

In Copies of the CST8207 Course Notes, see the example use of fgrep with shell GLOB patterns to match *.txt files in these oldnotes and newnotes directories. The GLOB pattern easily generates a huge list of file names for fgrep to search inside.

  1. In the old course notes from last year, use one command to search inside all the .txt files for the word Filezilla (spelled exactly as shown, case-sensitive). Only three lines of text should display, from three files. Each line of text should be preceded by the file name in which it was found. (The word count of the output must be 3 39 323.)

    Hint: You will need to use the same GLOB pattern you used earlier in this assginment to match all the .txt files under oldnotes. This time, use the GLOB pattern to make the shell give all the file names to the command that searches for text inside all those files. No pipes are needed to find these lines; use just one command with no options and a single GLOB pattern. If you see more than three lines of output, you are likely using options that make the search case-insensitive. If your word count is wrong because the file names are missing, you are likely using unnecessary pipes. No pipes are needed to find the three lines.

  2. Repeat the above on all the *.txt files, but add the searching option that ignores case distinctions when matching lines in the files (RTFM). Now, 12 lines are found in five different files and the word count should be 12 118 1165.

    Hint: These text-searching commands are case-sensitive by default – searching inside files for lines containing abc won’t find any lines containing ABC unless you use an option to ignore case distinctions during the search. (What option? RTFM)

zillalines.txt

  1. Redirect the above lines of output into a file named zillalines.txt under your Base Directory. The word count of this file should match the one above.

Run the Checking Program to verify your work so far.

4.6 The cracker WAREZ 100 files

The “story” here is that a malicious cracker has dumped a bunch of WAREZ files in a directory on the server and has hidden them among thousands of other files. (See https://en.wikipedia.org/wiki/Warez.) Your job is to take a copy of the WAREZ files, and only the WAREZ files, for use in a court case. You must not touch or copy any other files, only the WAREZ files.

  1. There is a directory named warez under the Source Directory. Hidden (really hidden) deeper under this directory is one single directory containing over 200,000 names.

    Use cd and the Hints below carefully to find this huge hidden directory and make this huge directory your current directory, so that you can experiment with the GLOB pattern you will need in the following questions.

    Hints: Be careful about typing ls in this directory without using any output pagination pipe – the amount of output may flood your terminal window for some time and even a ^C interrupt may take a minute or two to interrupt the command! One way to avoid flooding your screen is by using ls | wc to count how many pathnames would be output on your screen before you do just ls. Be careful!

    Hints: This isn’t a maze. There is only one path down to the huge hidden directory inside the warez directory, though the way is hidden. Remember not to type ls in this large directory, when you find it, because the output is very large!

Do not continue until you have found the directory containing the huge number of files and made it your current directory.

Exactly 100 files in this huge directory (your current directory) have names that contain your userid (which must be matched lower-case) followed somewhere later by the text string warez, where warez is case-insensitive and may appear in any combination of upper- and lower-case letters, e.g. warez,Warez,wArez,waREz, etc.

Any amount of text may appear before your userid, between your userid and the warez, and after the warez.

Some sample file names for userid abcd0001 might look like these (note that the warez word must always follow the userid in all the required file names):

Many of the file names are up to 100 characters long.

warez

  1. Using one single copy command and a single shell GLOB pattern, copy all 100 (exactly 100) of these cracker files (and no others) into a new directory named warez that you must create in your own Base Directory. Make sure you preserve the modify times of the copied files, as you did in a previous lab. (In this simulation, all the files are empty.)

    Hints: Before you try to copy any files, use echo with the GLOB pattern into word count to verify your GLOB patterns before using them. The echo with GLOB pattern should produce exactly 100 pathnames.

    The shell must correctly expand the GLOB pattern argument to echo before you try to use the same GLOB pattern in a copy command. Once you can echo the 100 pathnames correctly, use exactly the same GLOB pattern to generate the source pathnames in a copy command.

    Do not use a pipe or find or fgrep to select the file names. Use only the copy command with a GLOB pattern for the source files, as you did in section 4.1 of Worksheet #04 HTML. The shell can do all the file name matching using the right GLOB pattern for the source files.

    Do not quote the shell GLOB patten. Quoting hides metacharacters and turns off shell GLOB patterns. You want the shell to expand the GLOB pattern for this task! (If you were passing a GLOB pattern as an expression in a find command, you would quote it so that the shell didn’t expand it. That is not what you are doing here.)

warezcopy.sh

  1. Put the copy command line that you used into file warezcopy.sh in your Base Directory. Pay attention to the file name extension in this file name.

    Hints: Make sure that the content of the file is exactly the same as the copy command you typed, with no special characters expanded. The number of blank-separated words in the file should be about four.

    Hints: The best way to put this command line in the file is to use a Linux text editor, or you can use the cat keyboard and EOF method from section 5.5a in Worksheet #05 HTML. Read this Warning:

Warning: It is tricky to use echo with redirection to put this command line into the file because the line contains shell metacharacters. You can’t just stick echo on the front of a command line that contains shell metacharacters such as GLOB patterns; the shell will expand all those metacharacters before the echo command runs. You will need special Quoting to make it work. You will need to hide all the shell metacharacters in the command line from the shell. Make sure the command line echoes correctly to the screen before you try to redirect it into the file. You can only redirect what you can see! Use a text editor instead!

  1. You can check your work by doing a listing of your warez directory and counting the number of names that were copied.

    All the files should have their original modify dates preserved – verify this.

Run the Checking Program to verify your work so far.

4.7 Finding files in a directory using a shell GLOB pattern

You need to understand Shell GLOB Patterns to do this task.

abcd0001.txt

  1. Under the Source Directory there is a name maze (four letters). What is the absolute path of this maze under that directory? Put the absolute pathname of this maze in that directory into a file in your Base Directory with a basename similar to abcd0001.txt, but use the basename that starts with your own Blackboard userid, not the fake userid abcd0001. Use your own userid in the file name.

    Save the actual absolute pathname, not a shell tilde short-cut for an absolute pathname. (Do not start the name with a tilde.) The file basename must be exactly 12 characters long. The absolute pathname of the maze itself is over 40 characters long.

    You will need this maze absolute pathname in several places, below.

  2. Use the ls command and a single shell GLOB pattern to display on your screen on separate lines the absolute paths of all names under the above maze directory that begin with your userid.

    Hints: Use the ls command (no options) with a single absolute path shell GLOB pattern as an argument, in a manner similar to how you displayed all the tty names in section 4.1 of Worksheet #04 HTML. Use the actual absolute pathname, not a shell tilde short-cut for an absolute pathname. Do not start the name with a tilde.

    Hints: You should see six absolute pathnames. One of the six absolute pathnames will end in abcd0001.txt where abcd0001 is your own userid. Each of the six absolute pathnames should contain seven forward slashes. The word count of the six output lines should be 6 6 349.

FirstMaze.txt

  1. When you have the correct ls command that generates six lines of absolute pathname output, redirect and save the six lines into file FirstMaze.txt in your Base Directory.

    Hints: The word count of the file should also be 6 6 349.

FirstMaze.sh

  1. Save the exact ls command line with GLOB pattern that you used in item 2 above into file FirstMaze.sh in your Base Directory. Pay attention to the file name extension in this file name.

    Hints: The file should contain only two blank-separated words: the command name and a single GLOB pattern. Do not save the redirection that you added in item 3 above. The word count of the file should show 1 2 57.

    Hints: Make sure that the content of the file is exactly the same as the ls command you typed in item 2, with no special characters expanded. The number of blank-separated words in the file should be exactly two: the command name and a single GLOB pattern argument. Running the command by typing sh -u FirstMaze.sh should print the six pathnames on your screen.

    Hints: The best way to put this command line in the file is to use a Linux text editor, or you can use the cat keyboard and EOF method from section 5.5a in Worksheet #05 HTML. Read this Warning:

Warning: It is tricky to use echo with redirection to put this command line into the file because the line contains shell metacharacters. You can’t just stick echo on the front of a command line that contains shell metacharacters such as GLOB patterns; the shell will expand the GLOB patterns before the echo command runs. You will need special Quoting to make it work. You will need to hide all the shell metacharacters in the command line from the shell. Make sure the command line echoes correctly to the screen before you try to redirect it into the file. You can only redirect what you can see! Use a text editor instead!

Run the Checking Program to verify your work so far.

These six pathnames are only six of the many file names in the maze that start with your userid. We need to find them all, in all the sub-directories, too.

4.8 Finding files recursively in a maze using a find GLOB pattern

You need to understand Shell GLOB Patterns and Finding Files to do this task.

GLOB patterns when expanded by your shell can only match names in one directory; they don’t recursively search all the directories in the entire maze. To find all the names in the maze that start with your userid, in all directories, we can’t use the shell to expand the GLOB pattern. We need to hide the GLOB pattern from the shell and pass the GLOB pattern to a command that recursively searches a directory. (You have used this command many times already.)

4.8.1 Quoting the GLOB Pattern

You must hide the GLOB pattern from the shell and pass it unchanged to the command that recursively searches directories. GLOB pattern metacharacters work the same way to match basenames, as shown in the examples in Finding Files. Do not let the shell expand the GLOB pattern!

We need to hide the GLOB patterns from the shell, since we want to pass the GLOB patterns unchanged to the command we use. Here’s how:

  1. Using the search tools in your web browser (not on the CLS), look for the string quote in the course notes web page on Searching for and finding files by name, size, use, modify time, etc. Read all the paragraphs containing this quote word (search multiple times) and remember the importance of quoting. You will need to know how to do this quoting when you start the finding and searching work for this task on the CLS, below.

howquote.txt

  1. In the first paragraph you found, above, put the example command line (showing the use of quotes around the *.txt argument that contains a GLOB character) into file howquote.txt in your Base Directory. The file must contain just the example command line text after the e.g. and it will be one line, three words, 19 characters, according to wc.

    If the count is wrong, look in the file to see what is wrong with the text. Does the file contain exactly the same text as the course notes? If not, edit the file and fix it.

    Hints: The best way to put this example line in the file is to use a Linux text editor, or you can use the cat keyboard and EOF method from section 5.5a in Worksheet #05 HTML. Read this Warning:

Warning: It is tricky to use echo with redirection to put this command line into the file because the line contains shell metacharacters. You can’t just stick echo on the front of a command line that contains shell metacharacters such as quotes; the shell will remove the quotes before the echo command runs. You will need special Quoting to make it work. You will need to hide all the shell metacharacters in the command line from the shell. Make sure the command line echoes correctly to the screen before you try to redirect it into the file. You can only redirect what you can see! Use a text editor instead!

Run the Checking Program to verify your work so far.

4.8.2 Absolute Path to the Maze

  1. Use the absolute pathname of the maze name in the Source Directory as an argument to ls along with an option that shows the long information about the pathname. (You already saved this maze pathname in a file, above.)

    Use the actual absolute pathname that you saved, not a shell tilde short-cut for an absolute pathname. (Do not start the name with a tilde.) Do not put a trailing slash on the pathname.

    Hints: You should see exactly one line of output. You have the right option to ls if the first word of the output is lrwxrwxrwx, indicating that maze is a symbolic link, not a directory.

    If the ls long listing gives you a directory listing full of files instead of one line starting with lrwxrwxrwx, make sure you are using the right option to ls and the correct Source Directory path from this assignment and not any previous assignment.

    The command you use should use one option and one absolute pathname (with no trailing slash).

We will learn more about symbolic links in a future assignment. For now, note that the maze symbolic link has an arrow that leads to the same directory maze used in Assignment #03 HTML. (See that assignment for details on the size of this maze.)

lscmd.sh

  1. Save the full and exact ls command line you just used into file lscmd.sh in your Base Directory. Pay attention to the file name extension in this file.

    Running the command by typing sh -u lscmd.sh should print the long information about the maze symlink.

infomaze.txt

  1. When you have the correct ls command line that generates one long line of output, redirect and save the output (one line) into file infomaze.txt under your Base Directory.

Run the Checking Program to verify your work so far.

4.8.3 Finding names starting with abcd0001

Again, in a manner similar to your previous assignments, you must find files in this maze, using the maze as the starting directory. The symbolic link requires some special handling, because the command that recursively finds files does not follow symbolic link arguments on the command line without using an option. You must choose one of these methods to search this symbolic link maze (choose one):

  1. Method 1: Use an option to the finding command that makes it follow symbolic links only while processing the command line arguments. Hint: RTFM, search for while processing, and do not use the -L option, OR
  2. Method 2: Make the maze your current directory and then recursively search the current directory. (A current directory can never be a symbolic link – it must be a real directory.)

You will choose one of the previous two starting directory methods to reach the maze when you start searching, below.

  1. As you know from a previous assignment, this maze contains many hidden sub-directories. With this maze as a starting directory using one of the two above methods, use a single command (no pipes needed) 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 match and output pathnames containing basenames such as abcd0001 and abcd0001YYY but not XXXabcd0001 or XXXabcd0001YYY or abcdYYYY where XXX and YYY can be any non-empty strings of characters. Your own userid must start every basename.

    Your single recursive command should find exactly 23 pathnames.

    Hint: You must use a single command (not a pipeline) that is good at Finding Files by a basename pattern to do this. Do not try to use cd and ls to find all the files; the maze is really, really big.

    Hint: You have previously used this recursive command many times without a pattern for the basename. This task requires you to pass to the command a GLOB pattern that matches your userid followed by zero or more characters. You must hide the GLOB pattern from expanseion by the shell.

    Hint: If you don’t find any pathnames, re-read the section on the two Methods for the starting directory, above.

    Hint: If you only find a few pathnames, or you get an error message from find such as find: paths must precede expression, re-read the section on Quoting the GLOB Pattern, above.

  2. When you see all 23 pathnames on your screen, take the same single command you used to find the names above and modify it to use the expression that makes the command show the full detailed attribute information about the names (including permissions, owner, size, date, etc.) instead of just the pathname. Use the same command; just remove -print and add the right expression.

    You will know you have the right expression if the output of the command is 23 lines and approximately 256 words (instead of 23 words).

    Hint: You know which expression to use from your answers in Worksheet #02 HTML and Worksheet #03 HTML and from reading the detailed attribute information paragraph at the end of Section 2 of the Finding Files notes.

You may want to review using pipes in Worksheet #05 HTML and Redirection and Pipes to do this next item.

foundmaze1.txt

  1. Pipe the 23 lines of pathname output of the above command into a sorting program and put the sorted output into file foundmaze1.txt under your Base Directory. The sorted file will still contain exactly the same number of lines and words as you counted, above.

findcmd1.sh

  1. Put the entire above two-command pipeline with redirection that you just used, into file findcmd1.sh in your Base Directory. Pay attention to the file name extension of this file name.

    Hint: Make sure the command you save in the file includes both the pipeline and the output redirection. If you run the command file using sh -u findcmd1.sh you should see no errors and no output on your screen. (All the output should go into the foundmaze1.txt output redirection file.)

    Hint: The best way to put this command line in the file is to use a Linux text editor, or you can use the cat keyboard and EOF method from section 5.5a in Worksheet #05 HTML. Read this Warning:

Warning: It is tricky to use echo with redirection to put this command line into the file because the line contains shell metacharacters. You can’t just stick echo on the front of a command line that contains shell metacharacters such pipes; the shell will execute the pipes before the echo command runs. You will need special Quoting to make it work. You will need to hide all the shell metacharacters in the command line from the shell. Make sure the command line echoes correctly to the screen before you try to redirect it into the file. You can only redirect what you can see! Use a text editor instead!

Run the Checking Program to verify your work so far.

4.8.4 Finding names containing abcd0001 anywhere

  1. In this same maze, use a single command (not a pipeline) to recursively find all pathnames with a basename that contains your eight-character userid anywhere in the name.

    For example, if your userid were abcd0001 then you might output pathnames containing basenames such as abcd0001, abcd0001YYY, XXXabcd0001, and XXXabcd0001YYY where XXX and YYY can be anything (zero or more characters). Your own userid will be somewhere in every basename.

    Your single recursive command should find exactly 47 pathnames.

    Hint: See the hints for the previous section. This command line is a simple modification of the previous one.

  2. When you see all 47 pathnames on your screen, take the same single command you used to find the names above modify it to use again the expression that makes the command show the detailed attribute information about the names, as you did above.

    You will know you have the right expression if the output of the command is 47 lines and approximately 535 words (instead of 47 words).

foundmaze2.txt

  1. Pipe the 47 lines of pathname output of the above command into a sorting program and put the reverse-sorted output into file foundmaze2.txt under your Base Directory. The reverse-sorted file will still contain exactly the same number of lines and words as you counted, above.

findcmd2.sh

  1. Put the entire above two-command pipeline with redirection that you just used, into file findcmd2.sh in your Base Directory.

    Hint: See the hints for the previous section. Make sure the command you save in the file includes both the pipeline and the output redirection. Run the file to make sure the saved command works.

Run the Checking Program to verify your work so far.

4.9 Three different O/S Text Files – Unix, Windows, Macintosh

You need to understand Finding Files and Text File Line End Differences to do this task.

  1. Somewhere under the warez directory in the Source Directory you used earlier for the WAREZ problem are exactly three non-empty files whose names contain your userid (lower-case) somewhere (anywhere) in the name. (Most of the other files in the WAREZ directory whose names contain your userid are empty files.)

    Use a command to recursively find and display these three non-empty (size larger than zero) files with your userid anywhere in the name.

    Hints: What command finds files based on expressions that can include both size and a basename that can be a GLOB-style pattern? You have used this command many times this term. See the end of Worksheet #02 HTML and the “multiple expressions” example in Finding Files.

    You will find your userid mentioned inside each file, but because the files are not all Unix/Linux text files, some of the text content may not display correctly on your terminal screen. The less command is better than cat when displaying files containing strange (e.g. unprintable) characters, but see also the “show-nonprinting” option to cat.

3filesOS

  1. When you know the three pathnames, manually copy each of these files (preserving modify times) to a new directory named 3filesOS that you must create in your Base Directory.

    Since there are only three file names, you can use your mouse to copy-and-paste the three long file names you need to copy, once you know their names. Be careful to use quoting to hide any blanks in the names from the shell.

    (Optional advanced use: You can also read this optional material on a better way to use find -exec and xargs.)

Unix Windows Macintosh

  1. In your 3filesOS directory, determine which operating system created each of the three non-empty files. Rename the Unix/Linux file to be Unix, the Windows file to be Windows and the Macintosh file to be Macintosh.

    Hints: In Assignment #02 HTML you used a command that can determine file type to identify the text inside a date.txt file. You will also find this command listed under Week 02 in the List of Commands in your notebook. Use this command and the notes on Text File Line End Differences to identify the special line endings of the Windows and Macintosh files.

Run the Checking Program to verify your work so far.

4.10 Appending to files

You need to understand Redirection and Pipes to do this task.

appendfile

  1. Count the lines, words, and characters in the file services under the /etc directory and put the count in file appendfile under your Base Directory. (Use the absolute pathname of the services file when you count and do not use any pipes.) The file appendfile should contain one line containing three numbers and an absolute pathname at the end. There is no file extension on this file; Linux doesn’t care.

  2. Extract just the last line of the same services file and append this one line to the end of the appendfile file, so that the file appendfile now has two lines in it (the word count line, and the last line of services).

    Hint: You know a command that shows any number of lines at the end of a file. Review your work in Worksheet #05 HTML and the notes on Redirection and Pipes.

  3. Append the count of the lines, words, and characters in the file protocols in the /etc directory to the end of file appendfile, so that the appendfile file now has three lines in it. (Use the absolute pathname of the protocols file when you count and do not use any pipes.)

  4. Extract just the first line of the same protocols file and append just this one line to the end of the appendfile file, so that the file appendfile now has four lines in it.

    Hint: You know a command that shows any number of lines at the start of a file. Review your work in Worksheet #05 HTML and the notes on Redirection and Pipes.

Confirm that the word count of the appendfile file gives 4 15 105. If you see the right number of lines but the other values differ, go back and re-read all the words in the sentences above, especially the sentences that start with the words “Use the”.

Run the Checking Program to verify your work so far.

4.11 Searching System Log Files: counting refused IP addresses

The Course Linux Server is on the open Internet and is under constant attack on its SSH login port. The Denyhosts intrusion protection system locks out attacking IP addresses so that they are refused when they try again. We will find the most common refused IP addresses.

You need to understand Redirection and Pipes to do this task, especially the section on Using successive filters in pipes.

The course notes file Selecting Fields with awk explains how to use the command that extracts fields from lines.

  1. Copy the six-command pipeline used in Example 2 given in Using successive filters in pipes and modify it as follows and then run it:

    1. If necessary, change the month in the example from Jan to be the first month of the current academic term (three letters, one upper-case, with a space following)
    2. Add on the end of the pipeline a seventh filter command that limits the output on the screen to the first six (6) lines.

    Hints: Do not change any other parts of the existing six commands in the pipeline. All you need to do is (possibly) change the month and add a seventh filter command. The first line of output will look similar to 8008 (116.31.116.24) and the last line (of six lines) will look similar to 95 (119.249.54.66).

refusedpipe.sh

  1. When the output is correct, put the new seven-command pipline you used into file refusedpipe.sh in the Base Directory. You can put it on separate lines with backslashes at the end of each line, as shown in the notes, or you can remove the backslashes and put it all on one long line.

    Typing sh -u refusedpipe.sh should print the six most active attack IP addresses for the one month on your screen. If it doesn’t do this, you haven’t copied the command line correctly. Check it!

You can debug your script file by running it like this: bash -ux refusedpipe.sh and making sure you see seven commands execute before the six lines of output appears.

  1. Edit the refusedpipe.sh file and add to the end of the file, underneath your seven-command pipeline, exactly seven numbered shell comments that explain briefly and in your own words the meaning of each of the seven commands used in the pipeline, using the comment format described below.

    Shell script comments start with the number-sign (or hash-tag) character # and extend to the end of the line. The seven numbered comment lines must have a syntax similar to this (though this is the wrong pipeline and wrong comments to use for this task):

    last idallen | awk '{ print $3 }' | grep '^[0-9]' | sort | uniq | wc -l
    # 1. last idallen: show last login lines only for user idallen
    # 2. awk '{ print $3 }': display only third field (IP address)
    # 3. grep '^[0-9]': select only lines starting with a digit
    # 4. sort: put IP addresses into sorted order
    # 5. uniq: throw away duplicate adjacent IP addresses, leaving only unique
    # 6. wc -l: count the number of unique IP addresses (number of lines)

    Comment Format: Since there are seven commands in your script pipeline, you will need to write exactly seven numbered comment lines to explain them. As you see in the above example, each of the seven comment lines starts at the left margin with the # comment character (no spaces in front), followed by a space, number, a period, space, the pipeline command name and options to which the comment refers, and then your own comment text written in your own words. Each comment text is written in your own words to explain what the command does in the pipeline. Do not copy words; write your own.

    Follow the syntax shown in the above example, and use your own words (don’t copy mine). Including the seven comment lines, your refusedpipe.sh file will be at least eight (or more) lines long.

Run the Checking Program to verify your work so far.

4.12 Searching System Log Files: counting attacks

The Course Linux Server is on the open Internet and is under constant attack on its SSH login port. The Denyhosts intrusion protection system locks out attacking IP addresses and logs the event. We will find the month in 2015 with the most locked out IP addresses.

  1. Write a command to count the number of lines containing the string new denied hosts in the denyhosts-2015 log file on the CLS. You should find 2154 matching lines in the file.

    Hints: This log file is in the same directory as the auth.log file used in the previous item and in most of the Weekly Class Notes. Use the absolute pathname of the log file in your command line; do not change directories.

    Hints: Look at the contants of the log file before you begin. My solution used one command name with no pipes needed. I used an option that counted the number of matching lines, as shown in the weekly course notes.

denycom1.sh

  1. When the output is correct, put the command line you used to generate the number 2154 into file denycom1.sh in the Base Directory.

    Typing sh -u denycom1.sh should print the number 2154 on your screen. If it doesn’t do this, you haven’t copied the command line correctly. Check it!

You can debug your script file by running it like this: bash -ux denycom1.sh and making sure you see the correct command execute before the output appears.

  1. Write a command pipeline (using pipes) to count the number of lines containing the string new denied hosts in only September 2015 in the denyhosts-2015 log file on the CLS. You should find 177 matching lines to count and the output should be the number 177.

    Hints: The Example 1 given in Using successive filters in pipes explains how you might find some lines in the auth.log file that were created in January. Apply what you learn there to solve this problem. Before you try, look at the denyhosts-2015 file and find out what format it uses to represent the date “September 2015”. You can’t just look for the text “September 2015” in the file; it’s not there. Look into the file to see the actual date format and create a filter command to search for that date format and count the lines. My solution used two command names with one pipe between. The second command used an option that counted the number of matching lines, as shown in the weekly course notes.

denycom2.sh

  1. When the command pipeline is correct, put the command pipeline you used to generate the number 177 into file denycom2.sh in the Base Directory.

    Typing sh -u denycom2.sh should print the number 177 on your screen. If it doesn’t do this, you haven’t copied the command line correctly. Check it!

You can debug your script file by running it like this: bash -ux denycom2.sh and making sure you see the correct commands in the pipeline execute before the output appears.

  1. Using your shell history and the command you used in the previous item, modify and redo the command a few times to manually find the number of denied hosts in each month in 2015. Use this to determine the month with the largest number of denied hosts (390).

    Hint: It’s one of the months before June.

denyhosts.txt

  1. When you find the month with the largest number of denied hosts, Put the first five lines and the last five lines of log entries for this month into file denyhosts.txt in the Base Directory.

    Hint: Use a command pipeline to generate the first five lines of log output for this month and save them, then modify the command pipeline slightly to generate the last five lines of log output for this month and append them to the file containing the first five lines. That is your answer. The first five lines should be from the start of the month and the last five lines should be from the end of the month. The word count of this ten-line file should be: 10 100 854 and the sum should be 28039.

Run the Checking Program to verify your work so far.

4.13 When you are done

That is all the tasks you need to do.

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 Blackboard 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

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 single file that is the output of the Checking Program 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.

  1. There is a Checking Program named assignment05check in the Source Directory on the CLS. You can execute this program by typing its (long) pathname into the shell as a command name:

    $ ~idallen/cst8207/16f/assignment05/assignment05check

    You will learn of ways to make this shorter in future assignments.

  2. When you are done, execute the above Checking Program as a command line on the CLS. This program will check your work, assign you a mark, and display the output on your screen.

    You may run the Checking Program as many times as you wish, allowing you 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 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 assignment05.txt in your Base Directory on the CLS, like this:

    $ ~idallen/cst8207/16f/assignment05/assignment05check >assignment05.txt
    $ less assignment05.txt
    • Use standard output redirection with that exact assignment05.txt file name.
    • Use that exact name. Case (upper/lower case letters) matters.
    • Be absolutely accurate, as if your marks depended on it.
    • Do not edit the output file; the format is fixed.
    • Make sure the file actually contains the output of the Checking Program!
    • The file should contain, near the bottom, a line starting with: YOUR MARK for
    • Really! MAKE SURE THE FILE HAS YOUR MARKS IN IT!
  4. Transfer the above single file assignment05.txt (containing the output from the Checking Program) from the CLS to your local computer.
    • You may want to refer to the File Transfer page for how to transfer the file.
    • Verify that the file still contains all the output from the Checking Program.
    • Do not edit or open and save this file on your local computer! Edited or damaged files will not be marked. Submit the file exactly as given.
    • The file should contain, near the bottom, a line starting with: YOUR MARK for
    • Really! MAKE SURE THE FILE YOU UPLOAD HAS YOUR MARKS IN IT!
  5. Upload the assignment05.txt file from your local computer to the correct Assignment area on Blackboard (with the exact name) before the due date:
    1. On your local computer use a web browser to log in to Blackboard and go to the Blackboard page for this course.
    2. Go to the Blackboard Assignments area for the course, in the left side-bar menu, and find the current assignment.
    3. Under Assignments, click on the underlined assignment05 link for this assignment.
      1. If this is your first upload, the Upload Assignment page will open directly; skip the next sentence.
      2. If you have already uploaded previously, the Review Submission History page will be open and you must use the Start New button at the bottom of the page to get to the Upload Assignment page.
    4. On the Upload Assignment page, scroll down and beside Attach File use Browse My Computer to find and attach your assignment05.txt file from your local computer. Make sure the assignment file has the correct name on your local computer before you attach it. Attach only your assignment05.txt file for upload. Do not attach any other file names.
    5. After you have attached the assignment05.txt file on the Upload Assignment page, scroll down to the bottom of the page and use the Submit button to actually upload your attached assignment05.txt file to Blackboard.
    6. Submit the file exactly as uploaded from the CLS.
    7. Do not submit an empty file. Do not submit any other file names.

    Use only Attach File, Browse My Computer on the Upload Assignment page. Do not enter any text into the Write Submission or Add Comments boxes on Blackboard; I do not read them. Use only the Attach File, Browse My Computer section followed by the Submit button. If you need to comment on any assignment submission, send me EMail.

    You can revise and upload the file more than once using the Start New button on the Review Submission History page to open a new Upload Assignment page. I only look at the most recent submission.

    You must upload the file with the correct name from your local computer; you cannot correct the name as you upload it to Blackboard.

  6. 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 uploaded submissions for this assignment. Each of your submissions is called an Attempt on this page. A drop-down list of all your attempts is available.
    1. Verify that your latest Attempt has the correct 16-character, lower-case file name under the SUBMISSION heading.
    2. The one file name must be the only thing under the SUBMISSION heading. Only the one file name is allowed.
    3. No COMMENTS heading should be visible on the page. Do not enter any comments when you upload an assignment.
    4. Click on the Download button to open and view the file you just uploaded. MAKE SURE THE FILE YOU JUST UPLOADED HAS YOUR MARKS IN IT!
    5. Save a screen capture of the Review Submission History page on your local computer, showing the single uploaded file name listed under SUBMISSION. If you want to claim that you uploaded the file and Blackboard lost it, you will need this screen capture to prove that you actually uploaded the file. (To date, Blackboard has never lost an uploaded file.)
    6. Make sure you have used Submit and not Save as Draft. I cannot mark draft assignments. Make sure you Submit.

    You will also see the Review Submission History page any time you already have an assignment attempt uploaded and you click on the underlined assignment05 link. You can use the Start New button on this page to re-upload your assignment as many times as you like.

    You cannot delete an assignment attempt, but you can always upload a new version. I only mark the latest version.

  7. 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!

READ ALL THE WORDS. OH PLEASE, PLEASE, PLEASE READ ALL THE WORDS!

Author: 
| Ian! D. Allen, BA, MMath  -  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/
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