Updated: 2013-04-09 17:40 EDT
23h59 (11:59pm) Saturday March 16, 2013 (end of Week 9)
temperature.sh
)mail_temperature
even more)Since we 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. Write the scripts according to the specifications, not according to the incomplete set of the mistakes detected by the Checking Program.
crontab
, and at
.Remember to READ ALL THE WORDS to work effectively and not waste time.
This is an overview of how you are expected to complete this assignment. Read all the words before you start working.
Complete the Tasks listed below on the Course Linux Server (CLS). Test your script using the given examples. Run a Checking Program to verify your work after you have run your own tests. Submit the output of the checking script to Blackboard before the due date.
Since we 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. Write the scripts according to the specifications, not according to the incomplete set of the mistakes detected by the Checking Program.
Some of the tasks below ask you to write a small executable shell script, based on the lecture notes and slides. All scripts should begin with the International Script Header you used for your previous assignments. When you have completed each script, ensure that it is executable, so that it can be run as ./scriptname.sh
.
Scripts must validate their arguments, even if they take no arguments. (A script that takes no arguments must not run if you give it arguments, since clearly you don’t know how to use it.) Error messages must be written in the style of Good Error Messages, as you did in the previous assignment. Always follow the Good Error Message with a Usage message that says how the script should be run.
When you are finished the tasks, leave the files, directories, cron
jobs, and at
jobs in place as part of your deliverables. Do not delete any assignment work until after the term is over! Assignments may be re-marked at any time; you must have your term work available right until term end.
The previous 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.
Remember to READ ALL THE WORDS to work effectively and not waste time.
All references to the “Source Directory” below are to the directory ~idallen/cst8177/13w/assignment06/
and that name starts with a tilde character followed by a userid with no intervening slash.
~/Assignments/assignment06
, in which you will create the files and scripts resulting from the following tasks.check
symbolic link needed to run the Checking Program.process_id.sh
./process_id.sh
username processsignaltrap.sh
which is located in the Source Directory. You’ll notice this script doesn’t print anything – it just sits there doing nothing, and you don’t get your bash
prompt back because the script isn’t finished yet. The bash
prompt won’t appear until the script process is finished or stopped.
^C
to try to interrupt this script process (send it an INT
signal).
INT
signal^Z
to send a STOP
signal to the script process.
bash
prompt back and see a message about the script process being Stopped
by the signal.bg
to resume the script process running in the background.process_id.sh
script to find and verify the process id of this script process.
TERM
signal (terminate) and notice that this too didn’t make it do the expected (clean up and die).KILL
signal.
KILL
signals can’t be ignored, so it should be gone – verify this.PID
of any process owned by root
or by another user, and send it a KILL
signal (or any signal).
mail
CommandThere are many text-mode email clients (“Mail User Agents”) for Linux. This assignment uses the one named
mutt
(man mutt
).
elinks
with the given options (reproduced below) to retrieve the Ottawa Weather URL http://text.www.weatheroffice.gc.ca/forecast/city_e.html?on-118
elinks -dump -no-numbering -no-references
URL?
in the URL will try to expand. Do not let that happen.elinks
defaults to fetching pages using the UTF8 character set, which may not display well on your screen. You can change the character set using the -dump-charset
option followed by a new character set. (Try ascii
, latin1
or the default utf8
.)elinks
output into grep
with some options to extract the line with the word Temperature:
and the line that follows it that is the actual temperature. The pipeline will print two lines.
temperature.sh
that prints out the current temperature for Ottawa. The active part of the script will be one line long, plus code to check the number of arguments (no arguments), plus the script header.
alias
in your script; use the full elinks
command line with the correct URL.mail
command and try sending yourself email:
echo "Testing mail command." | mail -s "Test"
abcd0001
@algonquinlive.com
mail
program.temperature.sh
weather script to your Algonquin email address with the subject: Current Ottawa Temperature
-dump-charset latin1
or -dump-charset ascii
to the elinks
command line in your temperature.sh
script.-dump-charset latin1
or -dump-charset ascii
to the elinks
command line in your temperature.sh
script.mail_temperature.sh
that will email the current Ottawa temperature to your Algonquin email address, or your phone.
temperature.sh
script to generate the temperature for the script pipeline.
elinks
line in this new mail script; your new script must email the output created by running your previous script.temperature.sh
script. (Of course, you won’t be able to fully test it without a working temperature.sh
script.)mail_temperature.sh
script in your own bin/
directory and name the link mail_temperature
mail_temperature
at a shell prompt to have the temperature sent to you. (If this doesn’t work, perhaps you haven’t set your PATH
in your .bashrc
as required in Section 4.6 of Assignment #02?)mail_temperature
is a very long name to type, find a way to create another name for this script that is shorter and faster to type. (You choose the name; nobody is looking.) (Hint: Perhaps another hard link, or perhaps a shell alias
?)crontab
and at
- The
crontab
command is used to create tasks that are run repeatedly by the systemcron
daemon program. These are commonly calledcron
jobs. You can create personalcron
jobs. There is also a system file containing systemcron
jobs.- The
at
command is used to create a task that runs only once at some future date and time. These are commonly calledat
jobs. There is no system file ofat
jobs, since these jobs only run once.
crontab
command and note the syntax used to install a new crontab
from a named file. Experiment with some crontab
lines that run in the near future to make sure you know how it works. (If you don’t redirect the output of your tests, you will need to use the mail
program to see the emailed output generated by your cron
jobs.)
mail_weather.crontab
text file containing a crontab
line designed to run your mail_temperature
program 10:14am every day. Use this exact name and this exact time in this file. You will need to experiment with times in the near future while you are testing the crontab
command, but make sure this file contains exactly the 10:14 time for marking.
crontab
file correctly even if you have not got a working mail_temperature
script. (Of course you won’t receive the correct output without a working mail_temperature
script.)crontab
command to submit your mail_weather.crontab
file to the crontab
system.cron
jobs and display them to make sure your 10:14 job is there.mail_temperature
script name and not the mail_temperature.sh
name, as specified?at
command and note the syntax used to schedule an at
job in the future. Experiment with some at
command lines that run in the near future to make sure you know how it works. (If you don’t redirect the output of your tests, you will need to use the mail
program to see the emailed output generated by your at
jobs.)
at
command to schedule a run of your mail_temperature
program at 10:00am, December 21, 2013. Use this exact name and this exact time.at
job numbers and display the list to make sure your December 21 job is there.
at
job will run. That is, display the actual command line that you submitted when you created the at
job.
at
is only one line long, how can you show only the command line itself and not all of the associated shell environment that is created as part of the job? (Hint: One command with one pipe.)mail_temperature
script name and not the mail_temperature.sh
name, as specified?When you are finished, run the Checking Program to create an overall mark.
Since we 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. Write the scripts according to the specifications, not according to the incomplete set of the mistakes detected by the Checking Program.
Since we 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. Write the scripts according to the specifications, not according to the incomplete set of the mistakes detected by the Checking Program.
Check your work a final time using the assignment06check
program symlink 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.
There is a Checking Program named assignment06check
in the Source Directory on the CLS. Create a symbolic link to this program named check
under your new assignment06
directory so that you can easily run the program to check your work and assign your work a mark. Note: You can create a symbolic link to this executable program but you do not have permission to read or copy the program file. To verify the symbolic link, try executing it.
Execute the above “check” program using its symbolic link. (Review the CST8207 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.
When you are done with checking this assignment, and you like what you see on your screen, redirect the output of the Checking Program into the text file assignment06.txt
under your assignment06
directory. Use the exact name assignment06.txt
in your assignment06
directory. You only get one chance to get the name correct. Case (upper/lower case letters) matters. Be absolutely accurate, as if your marks depended on it. Do not edit the file.
Transfer the above assignment06.txt
file from the CLS to your local computer and verify its contents. Do not edit this file! No empty files, please! Edited or damaged files will not be marked. You may want to refer to this term’s updated File Transfer notes.
Submit the assignment06.txt
file under the correct Assignment area on Blackboard (with the exact name) before the due date. Upload the file via the assignment06 “Upload Assignment” facility in Blackboard: click on the underlined assignment06 link in Blackboard. Use “Attach File” and “Submit” to upload your plain text file.
No word-processor documents. Do not send email. Use only “Attach File”. Do not enter any text into the Submission or Comments boxes on Blackboard; I do not read them. Use only the “Attach File” section followed by the Submit button. (If you want to send me comments about your assignment, use email.)
Your instructor may also mark the assignment06
directory in your CLS account after the due date. Leave everything there on the CLS. Do not delete any assignment work from the CLS until after the term is over!
Use the exact file name given above. Upload only one single file of plain text, not HTML, not MSWord. No fonts, no word-processing. Plain text only.
Did I mention that the format is plain text (suitable for VIM/Nano/Pico/Gedit or Notepad)?
NO EMAIL, WORD PROCESSOR, PDF, RTF, or HTML DOCUMENTS ACCEPTED.
No marks are awarded for submitting under the wrong assignment number or for using the wrong file name. Use the exact name given above.
WARNING: Some inattentive students don’t read all these words. Don’t make that mistake! Be exact.
READ ALL THE WORDS. OH PLEASE, PLEASE, PLEASE READ ALL THE WORDS!
Author:
| Todd Kelley / Richard Donnelly and
| Ian! D. Allen - idallen@idallen.ca - Ottawa, Ontario, Canada
| Home Page: http://idallen.com/ Contact Improv: http://contactimprov.ca/
| College professor (Free/Libre GNU+Linux) at: http://teaching.idallen.com/
| Defend digital freedom: http://eff.org/ and have fun: http://fools.ca/
Plain Text - plain text version of this page in Pandoc Markdown format
Author Ian! D. Allen