Author Ian! D. Allen
Updated: 2015-09-06 00:38 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) Friday October 3, 2014 (end of Week 5)
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 is an overview of how you are expected to complete this assignment. Read all the words before you start working.
For full marks, follow these directions exactly.
You are given a file of somewhat random text, and a set of descriptions of sets of lines in that file. For each description, you are to produce a command with a regular expression that will select the described set of lines. You will initially test your regular expressions on the interactive shell command line, and when you are satisfied with each one, you will put the command you used into a shell script.
You can use a 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.)
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.
You will create file system structure in your HOME directory on the CLS, with various directories, files, and links. When you are finished the tasks, leave these files, directories, and links in place as part of your deliverables on the CLS. 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.
All references to the “Source Directory” below are to the CLS directory ~idallen/cst8177/14f/assignment03/ 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).
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.
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.
Make an assignment03 directory in the same directory as you made assignment02 in a previous assignment.
This
assignment03directory is the Base Directory for most pathnames in this assignment. Store your files and answers in this Base Directory.
Follow the instructions in the first two steps at the start of Checking Program below to create a working symbolic link to the executable Checking Program.
The input text file test_input.txt in the Source Directory contains many lines of text. Put a soft link to this input file in your Base Directory. Use the same name for the link.
Check your work so far using the checking program symlink.
Below, in the Labelled Descriptions section, you are given labelled descriptions of lines to find in the input text file test_input.txt. For each labelled description you will repeat these two steps (described in detail below):
grep command using a single basic (not extended) regular expression that will select and display only the described lines of text, and nothing more, from the input file. Do not use any options to grep, except possibly for the last question; see below. You do not need multiple expressions or any extended regular expressions or special expressions, except possibly for the last question. Use basic regular expressions.grep command into its own shell script.Each set of lines to be found is labelled below with a label. The label is the first word in the section, followed by a colon. For example, the following example description is labelled bar:
bar: lines that contain the word barbarRepeat the following steps for each of the labelled descriptions:
Make your current working directory the Base Directory (the directory containing the new symlink you made to the test_input.txt file) if it is not already so.
You must find lines in the test_input.txt file using a single grep command with a regular expression pattern. Type directly at the command line your initial attempt at a grep command that finds the lines, and view the result on your screen.
For the example given above with the label bar, a grep command you might try to match lines containing barbar could be:
$ grep 'barbar' test_input.txtThe correct answer output on your screen for each problem below will vary between a few and a few dozen lines, depending on the problem.
No pipes are allowed. Use only a single grep command, imitating the above command format. No grep options or extended regular expressions are allowed except as explained in the last problem.
If you’re not satisfied with the output you see, use up-arrow to retrieve the previous command, and make changes to the regular expression, then re-run the new command. Repeat the this step over and over on the interactive command line until you’re satisfied with the output on your screen and want to check your answer.
To check your answer, use up-arrow to retrieve the command, and modify it to pipe the output of your command into the wc program, then do the same, changing wc to sum. Compare the output of wc and sum with the expected values output by the Checking Program.
For the example given above with the label bar, the checking pipelines would be done like this, in this order:
$ grep 'barbar' test_input.txt
$ grep 'barbar' test_input.txt | wc
$ grep 'barbar' test_input.txt | sumThe 'barbar' string is the quoted basic regular expression.
If the word count or checksum values differ from those expected values output by the Checking Program, you need to fix your regular expression. Use up-arrow to retrieve the command, make your changes to the regular expression, and re-run the command until you get it right.
Do not save the output of the Checking Program; the test file may change at any time to include new test cases, so the word count and checksums may change at any time.
When you are satisfied with your answer as typed on the command line, use a text editor to create in your Base Directory an executable shell script whose name is the label name followed by an .sh extension, e.g. bar.sh. Copy the working grep command from the command line into the last line of the new shell script. Only put the grep command into the script, not any pipelines or checking. This executable script must run only your grep command.
For the example given above with the label bar, the script name must be bar.sh in the Base Directory.
The first few lines of every shell script must correspond exactly to the Script Header described in class.
The last line of every script will be your grep command. Do not redirect or pipe the output of your command into anything inside the script – the script should produce the correct lines of output from test_input.txt on your screen so that it can be checked.
Do not put any lines into your script other than the Script Header, the single grep command line, and optional blank or comment lines.
You can also check the output of your script using the wc and sum commands, similar to the way you checked the original grep command. The script must output exactly the same lines as the original grep command that you put into it. The results should be identical:
$ grep 'barbar' test_input.txt | wc
$ ./bar.sh | wc
$ grep 'barbar' test_input.txt | sum
$ ./bar.sh | sumRepeat the 8 steps in this section for each of the Labelled Descriptions below.
NOTE: When it comes time to create your second and subsequent scripts, copy the previous script to the new label name rather than starting from scratch every time. Run the Checking Program to make sure you have copied the Script Header correctly.
Do not put any lines into your script other than the Script Header, the single grep command line, and optional blank or comment lines.
Your scripts must give the correct output word count and checksum results when searching in this test_input.txt test file. If the output is incorrect, you will be told what the correct values should be in the error message. Do not save this message – the testing file may change at any time during the assignment and your scripts must still match the correct lines.
Write the basic regular expressions to match the given pattern specifications, not to match the particular set of lines in the given test file(s). I may come up with other test cases even after the due date of the assignment; your script loses marks if it fails these tests because it doesn’t do what the specification says it must do. You may have to write your own test cases, to be sure you got it right.
I’ve also set up the checking program to detect failure to protect special characters from shell GLOB expansion. If your expression works in your account but not when the checking script runs it, this may be your problem. You may also see “Permission denied” errors if this is the problem. Fix your script.
Repeat the 8 steps of the above section for each of these labelled items below. None of these expressions except the very last one require any options to grep, nor multiple expressions, nor do they require any extended regular expressions.
All except the last must be solved with no options and only one single basic regular expression.
All the points below have the following format:
label: description of desired grep output from in file test_input.txtHere are the names of the patterns (and scripts) you must create:
upper: lines containing at least one upper case alphabetic character.
control: lines containing at least one control character. (When checking your output, you can make control characters visible using the -vT options to the cat command, otherwise they won’t show on your screen. Do not put the cat command in your script.)
punct: lines containing at least one punctuation character.
blank: blank lines. (A blank line contains only zero or more Whitespace characters and no other kinds of characters.)
only_alpha: non-empty lines containing only alphabetic characters. (“Non-empty” means there has to be at least one character.)
only_digit: non-empty lines containing only digits.
only_alnum: non-empty lines containing only alphanumeric characters.
only_upper: non-empty lines containing only upper case characters.
no_white: lines containing no Whitespace characters. Another way of saying this is: lines containing zero or more only non-Whitespace characters.
no_num_white: lines containing no Whitespace or digit characters. Another way of saying this is: lines containing zero or more only non-Whitespace non-digit characters.
empty: empty lines. (An empty line means nothing on the line, not even Whitespace characters. The line contains no characters.)
plus: lines containing at least one plus + character.
question: lines containing at least one question mark ? character.
backslash: lines containing at least one backslash \ character.
caret: lines containing at least one circumflex/caret ^ character.
star: lines containing at least one asterisk * character.
dot: lines containing at least one period . character.
square: lines containing at least one square bracket [ or ] character.
begin_end: lines that start with the exact five characters begin and that end with the exact three characters end. (Any other characters might appear between the begin and the end.)
AB: lines containing A and B, capitalized and in that order but not necessarily right next to each other. Another way of saying this is: lines containing a B following an A.
first: lines that start with optional Whitespace, then the string first.
capital: lines that contain the string Capital where the initial letter C must be upper-case but the rest of the letters could be either case, e.g. CAPTIAL, CaPiTaL, etc..
first_last: lines that start with the exact five characters first preceded by any amount of Whitespace and that end with the exact four characters last followed by any amount of Whitespace. (Any other characters might appear between the first and the last, but only optional Whitespace is allowed before first and after last.) (Hint: Another way of saying this: The line starts with optional Whitespace, followed by first, followed by anything, followed by last, followed by optional Whitespace, and then the end of the line.)
phone: lines that contain a seven-(or more)-digit number with one or more dashes between the group of three (or more) digits and the group of four (or more) digits. These should match: 555-1212, 555555-----121212121212, x555-1212x, x555---1212x, x999555-1212x, x555-1212999x x999555-1212999x, but these would not match: 555-121x, x55-1212, 5551212
better_phone: lines that contain a seven-digit number, surrounded before and after with non-digit characters, with one or more underscores, dashes, or periods between the third and fourth digits. These should match: x555-1212x, x555.1212x, x555_-.1212x, x555--__..-_.1212x but these would not match: 555555-----121212121212, x999555-1212x, x555-1212999x x999555-1212999x, 555-121x, x55-1212, 5551212
password: lines containing password or passwd, with the p optionally capitalized. These would match: Password, password, Passwd, but these would not match Pass, passwD, paSsword, passw, or passd. Hint: There is a solution to this that uses an option to permit grep to use multiple search patterns, or you can use a single extended regular expression. This is the only question in which you may use an option or extended regexp.
Check your work so far using the checking program symlink.
Do not save the output of the Checking Program; the test file may change at any time to include new test cases, so the word count and checksums may change at any time.
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.
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.
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.
There is a Checking Program named assignment03check in the Source Directory on the CLS. Create a Symbolic Link to this program named check under your new Base Directory on the CLS so that you can easily run the program to check your work and assign your work a mark on the CLS. Note: You can create a symbolic link to this executable program but you do not have permission to read or copy the program file.
Execute the above check program on the CLS using its 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.
assignment03.txt under your Base Directory on the CLS. Use that exact name. Case (upper/lower case letters) matters. Be absolutely accurate, as if your marks depended on it.
YOUR MARK forassignment03.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.
YOUR MARK forassignment03.txt file from your local computer to the correct Assignment area on Blackboard (with the exact name) before the due date:
Use only Attach File on the Upload Assignment page. Do not enter any text into the Text Submission or Comments boxes on Blackboard; I do not read them. Use only the Attach File 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.
You will also see the Review Submission History page any time you already have an assignment attempt uploaded and you click on the underlined assignment03 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.
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!
I do not accept any assignment submissions by email. Use only the Blackboard Attach File. No word processor documents. Plain Text only.
Use the exact file name given above. Upload only one single file of Linux-format plain text, not HTML, not RTF, not MSWord. No fonts, no word-processing. Linux plain text only.
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 16-character, lower-case 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 Ian! D. Allen