3.1 Searching the course notes

The previous term’s course notes are always available on the Internet here: CST8207 GNU/Linux Operating Systems I.

All the current and previous terms notes files are also stored on the CLS. You can learn about how to read and search these notes 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. The current CST8177 term notes are searchable there, too!

3.2 The Source Directory

All references to the “Source Directory” below are to the CLS directory ~idallen/cst8177/13w/assignment10/ and that name starts with a tilde character followed by a userid with no intervening slash.

4.1 Set Up

1. Complete your CentOS 5.8 VM Installation and Verification.
   • Make sure it passes the checks for disk sizes and package counts.
2. Complete these critical system administration tasks required in Assignment #07:
   1. create the sudoers group
   2. create your own account
   3. install and configure the NTP package
   4. copy your start-up files
3. Complete these critical system administration tasks required in Assignment #09:
   1. adjust your PATH for sysadmin work
   2. add a disk
   3. migrate /home directory to its own file system with mounted with quota options
   4. grow the root file system
   5. install VMware Tools

4. On the Course Linux Server, make the directory ~/Assignments/assignment10, in which some information will be stored related to this assignment, and also Create the check symbolic link needed to run the Checking Program.

5. In your own account in your CentOS 5.8 VM, also make the directory ~/Assignments/assignment10

6. Create a snapshot of your CentOS 5.8 VM.
   • Enter a comment explaining where and when you took this snapshot.
   • You can restore back to this snapshot if anything goes wrong.

4.2 Clean up groups from Assignment 09

In Assignment #07 Bulk User Management, you deleted user010 and user011 but their corresponding groups may have been left behind.

1. Delete the user010 and user011 groups, if they are still present on your machine.
   • You may see an error about removing the shadow group entry, because the newusers command did not create shadow group entries. Ignore the error – the groups don’t exist in the group shadow file.

4.3 Managing user quotas

You must have /home mounted on its own file system to do this section. You did that in Assignment #09.

Refer to Red Hat Quotas

1. Take your CentOS VM into single user mode.

2. Make sure your /home file system is mounted with quotas enabled. (You added quota options in Assignment #09.)

3. Use the quotacheck command with options appropriate to initialize the group quota file and user quota file for the /home filesystem.

4. Enable quotas (turn quotas on) for the /home filesystem.
   • Run the quota command as User 100 and ensure you see no quotas.
   • If you see the error quota: Can't open quotafile /home/aquota.user: Permission denied then you forgot to turn quotas on.
5. For User 100, set the following (unrealistic) test quota values:
   • soft block limit: 500KB worth of 1K blocks (500)
   • hard block limit: 700KB worth of 1K blocks (700)
   • soft inode limit: 5
   • hard inode limit: 6

6. Generate an overall /home file system quota report for all users and verify that User 100 has the correct limits. This is a full quota report, so it should have over 100 lines. Generate it again, redirecting the output to assignment10/repquota.txt

7. Change the ownership and group of this quota report file to yourself and your group. (Always change files stored in your own account to your own sysadmin userid.)

8. Take your CentOS VM back to runlevel 3 and log in as your sysadmin account.
   • Verify you are in runlevel 3 with the appropriate command.
9. Use sudo to run su - user100 to simulate a full login as User 100. Do all the following section as user100 in the user100 home directory:

   1. Exceed the soft block limit by creating a 600KB file with this command:

      $ whoami
      user100
      $ pwd
      /home/user100
      $ dd if=/dev/zero of=bigfile1 bs=1K count=600

      Creating this file will generate a quota exceeded message on the system console, because you are now over the soft limit on the number of files you can create. (If you are logged in via a terminal program, not on the VMware console, you may not see the quota exceeded warning message.)

      Note that even though you got a quota exceeded warning message on the console, all 600KB were actually copied into the output file. You only exceeded the soft quota, not the hard quota.

   2. Display the quota information and note the number of blocks used and the number of pathnames (files). You should see that the number of blocks used exceeds the soft quota but not the hard quota.

   3. Run the same quota information command again and redirect the output to a file named user100_quota.txt in the user100 home directory. This is just the user100 quota information, so it should be only three lines:

      $ whoami
      user100
      $ pwd
      /home/user100
      $ wc user100_quota.txt
      3  24 201 user100_quota.txt

      You did read the words above about running all the commands in this section as user100, right?

   4. View the contents of user100_quota.txt
      • Note how the number of pathnames (files) increased in the file. Why did the number increase before the quota command ran?
      • Note how the number of blocks did not increase in the file.
      • Display the quota again (without redirection) and note that the number of blocks has now gone up.
      • Why did the increased number of blocks not go into the redirection output file? Answers are Here

   5. Run ls to display a long listing of all the pathnames in the user100 home directory, including hidden names. The number of pathnames listed as being owned by user100 should be exactly the same as the number of files given in the user100_quota.txt file you created.

10. Type exit to revert back to your sysadmin self.

11. Use sudo to generate another overall /home file system quota report for all users, redirecting the output into the file assignment10/repquota_grace.txt

12. View assignment10/repquota_grace.txt and verify that it is consistent with the numbers in the user100_quota.txt file.

13. Become User 100 again and do the following in the home directory:

    1. Try to create another file, as follows. The command will give a “quota exceeded” message when the hard quota limit is reached:

       $ whoami
       user100
       $ pwd
       /home/user100
       $ dd if=/dev/zero of=bigfile2 bs=1K count=200

       You will see a quota error message from the dd command part-way through the file creation. Note that this time the output file does not contain the expected 200KB of data. The file is truncated because the hard quota limit was reached. You are not allowed to use any more disk blocks.

    2. Display the quota information as you did before and note that the hard block limit has been reached.
       • The number of files should be listed as 5 if there is a .bash_history file (there should be), and 4 if not.
    3. Create an empty file named smallfile and note:
       • Creating even an empty file will generate a quota exceeded message on the system console, because you are now over the soft limit on the number of files you can create (only 5).
       • If you are logged in via a terminal program, not on the VMware console, you may not see the file limit quota warning message.
       • You will see the quota exceeded message when the account has more than 5 files (the soft limit) in it.
       • After creating one or two more empty files, you will find that you get error messages and can’t create any more, because you hit the hard limit on the number of files you can create (max 6). Programs trying to create new files or directories will fail and return error messages.
       • Note that you can create hard links to existing files, since hard links only create new names, not new disk space.
       • You cannot create symbolic links, since symbolic links require disk space to store the link pathname.
       • You cannot create directories either, since a directory is considered a file for the purpose of quotas. (Anything that requires a new inode is considered a file here.)
    4. Display the quota information and verify that both the block and files quotas have hit their hard limits for this user.

    5. Type exit to revert back to your sysadmin self.

14. As your sysadmin user, generate another quota report, redirecting the output into your own file assignment10/repquota_hard.txt
    • Make sure you do this as your sysadmin user so that the owner of the redirection output file is your sysadmin user, so that the updated quota information includes this new file.
15. Put the difference between assignment10/repquota_{grace,hard}.txt into assignment10/repquota_diff.txt and view the file to verify that the changes in usage look right:
    • Exactly two users’ usage should have changed. If you do not see exactly two users, review all the words on the previous step.
    • Nothing should be shown for the root user. No changes.
    • If you see any changes for the root user, or no changes for your own userid, you did not create the repquota_hard.txt file correctly using sudo from your own sysadmin account. Delete the file and review all the words on the previous step.

16. Copy the user100 file named user100_quota.txt into your own assignment10 directory. (Needs privilege; you know what to do.)

17. Change the ownership and group of all files in your own assignment10 directory to your own sysadmin account.

4.4 Exploring SysVinit

1. Do the following tasks on the console (in the VMware window) of your VM.

2. Edit your inittab file to configure your system so that it boots by default into runlevel 2. (This changes one character in the file.) The changed inittab should have these wc and sum numbers:
   • Before: 53 229 1666 and 64040 2
   • After: 53 229 1666 and 59929 2

3. Reboot your system, and after it comes back up, log in and display the runlevel to verify that it is in runlevel 2.

4. Take a listing of all the processes running on your system using ps -e and redirect the output to assignment10/pse_rc_2_normal.txt (approximately 63 lines).

5. Edit your system’s inittab file. Disable by commenting out the one line that begins with the identifier l2
   • To comment out a line, insert a # at the beginning of the line so that it becomes a comment line.
   • The changed inittab should have these wc and sum numbers:
     • Before: 53 229 1666 and 59929 2
     • After: 53 229 1667 and 60289 2
   • The inittab man page calls the rightmost colon-delimited field on a line (the fourth field) the processfield. (RTFM) Notice the name of the script (the process) that your l2 edit has disabled.
   • When you next reboot the system, the services in runlevel 2 will not be started, because this runlevel 2 script will not run to start them.

6. Reboot your system, and after it comes back up, log in and display the runlevel to verify that it is still in runlevel 2.

7. Even though the system has booted into runlevel 2, the usual set of processes that run in runlevel 2 have not been started, because of the missing l2 line that you disabled above.
   • Take another listing of all the processes running on your system using ps -e and redirect the output to assignment10/pse_rc_2_gone.txt (approximately 42 lines).

8. Count the number of lines (number of processes) in each of assignment10/pse_rc_2_{normal,gone}.txt; one file should be about 20 lines bigger than the other file, since about 20 processes were not started by the missing l2 script.

9. Consider the SSH service provided by a process called sshd. Do a grep for sshd in pse*, and notice that it is present in the normal file but not in the gone file.

10. OPTIONAL: You have enough scripting knowledge to understand how the system actually finds and starts all the processes in a runlevel. Skip this section and come back to it later if you are curious.
    1. This numbered section is OPTIONAL. You do not have to do it.
    2. Display the rc script file that’s specified as the process to carry out in the l2 entry in the inittab file that you had commented out earlier.
    3. Find the two for loops in that script, and read the comment line above each for loop.
    4. The script code in those for loops may be a bit daunting, so let’s do a few grep commands on that rc script file:
       1. grep for the word for and read the output carefully. Note the loop variable name for each loop, and what it is iterating over.
       2. grep for the word stop and read the output carefully. Note that you have found that the word stop is being used as an argument (to what? consider the for loops).
       3. grep for the word start and read the output carefully. Note that you have found that the word start is being used as an argument. (to what? consider the for loops).

11. Recall the script (process) line that you disabled in the inittab file, above. Use sudo to manually run this script and its number 2 argument. Running this process (script) should start all the missing runlevel 2 processes that were not started at boot time.

12. Count the number of processes running (ps -e).
    • The list of processes running now should almost match the list of processes you saved in the pse_rc_2_normal.txt file.
    • The system is now fully in runlevel 2, with the correct set of runlevel 2 processes started (including the missing sshd).

13. Restore the l2 entry in your system’s inittab file. (Remove the comment character from the start of the line.)

Your system will continue to boot into runlevel 2 for the rest of this lab. Do not change the runlevel back to its previous value.

4.5 Exploring chkconfig

We’ll consider the ntpd service and runlevel 3. We’ll look at the contents of the rc3.d directory while ntpd is set on for runlevel 3. Then we’ll turn ntpd off for runlevel 3, and look at the contents of the rc3.d directory again to see how it changed.

1. View the top of the script /etc/init.d/ntpd and note the lines for chkconfig control. Put the line that indicates the chkconfig default runlevels and start and stop priority numbers into assignment10/ntpd_chkconfig.txt

   $ wc ntpd_chkconfig.txt
   1  5 21 ntpd_chkconfig.txt
   $ sum ntpd_chkconfig.txt
   09004     1

2. Run the command to display the runlevels for which the ntpd service is on or off. Redirect the output of this command into assignment10/ntpd_before.txt

   $ wc ntpd_before.txt
   1  8 54 ntpd_before.txt
   $ sum ntpd_before.txt
   42633     1

3. Take a long ls listing of /etc/rc.d/rc3.d/ and put this listing into assignment10/rc3d_before.txt

4. Run a grep command for ntpd in the rc3d_before.txt file, and put the output into assignment10/rc3d_ntpd_before.txt (should be one line). Verify the name of the symbolic link for ntpd in rc3d_ntpd_before.txt against the start priority number in ntpd_chkconfig.txt

   $ wc -lw rc3d_ntpd_before.txt
   1 11 rc3d_ntpd_before.txt

5. Use chkconfig to turn ntpd off in runlevel 3.

6. Run the command to display the runlevels for which the ntpd service is on or off, and check to be sure it’s off in runlevel 3, but the other runlevels are unchanged. Redirect the output of this command into assignment10/ntpd_after.txt

   $ wc ntpd_after.txt
   1  8 55 ntpd_after.txt
   $ sum ntpd_after.txt
   65203     1

7. Now that you’ve used chkconfig to turn ntpd off in runlevel 3, take another long listing of /etc/rc.d/rc3.d and put the output into assignment10/rc3d_after.txt

8. Run a grep command for ntpd in the rc3d_after.txt file, and put the output into assignment10/rc3d_ntpd_after.txt (should be one line). Verify the name of the script in rc3d_ntpd_after.txt against the start or stop priority number in ntpd_chkconfig.txt

   $ wc -lw rc3d_ntpd_after.txt
   1 11 rc3d_ntpd_after.txt

9. Run the diff command on rc3d_{before,after}.txt to see what the chkconfig command did. You should see one symbolic link has been removed, and one symbolic link has been created.

4.6 Logging

We’ll look at the logging of ssh activity. Then, we’ll change the file that ssh logging goes to, and change it back.

1. View the configuration file for syslog, and find the line dealing with the authpriv facility (the line that starts with the word authpriv). Put this line into assignment10/syslog_authpriv.txt

   $ wc syslog_authpriv.txt
   1  2 32 syslog_authpriv.txt
   $ sum syslog_authpriv.txt
   35835     1

2. View the configuration file for the SSH service daemon sshd named /etc/ssh/sshd_config and find the Logging section. Copy the active Logging configuration line (it starts with the word SyslogFacility) into the file assignment10/sshd_logging.txt

   $ wc sshd_logging.txt
   1  2 24 sshd_logging.txt
   $ sum sshd_logging.txt
   50989     1

   Remember the name of this sshd configuration file and the location of this syslog line. You will need to edit it, below.

3. Notice the correspondence between the contents of syslog_authpriv.txt and sshd_logging.txt and determine the file that sshd log entries are added to.

4. In one window (console, or putty, or ssh), use the tail -f command with sudo to watch the file that sshd log entries go to.

5. In another window, log in with ssh or putty, and observe the output of your tail -f command.

6. Still in the same ssh / putty window from the last step, use the sudo command to run head on the /etc/shadow file, and observe additions to to the log file on which you’re running the tail -f command. (where do sudo invocations get logged?)

7. Stop the tail -f with ^C and then put the last 20 lines of that log file into assignment10/ssh_sudo_log.txt
   1. View this file to be sure it includes the output you saw in the previous steps.
   2. If the file doesn’t contain those lines, then redirect a tail -f of the log file to ssh_sudo_log.txt, and repeat the ssh and sudo steps to be sure the logging output goes into ssh_sudo_log.txt
8. Recall the name of the sshd configuration file viewed earlier. Edit that file to make the SSH service daemon switch from using the AUTHPRIV to the AUTH logging facility by uncommenting one line and commenting out another.
   • When you’re done the wc on the file will be the same (119 397 3332) and the sum will change from 59355 4 to 47916 4.

9. Restart the sshd service.

10. View the syslog config file and put the line that controls the auth facility (hint: look for a “catch-all”) into assignment10/syslog_auth.txt

    $ wc syslog_auth.txt
     1  2 60 syslog_auth.txt
    $ sum syslog_auth.txt
    30346     1

11. Similarly to how you monitored sshd activity before, run tail -f on the log file corresponding to the auth facility, which is now used for sshd logging.

12. Similarly to before, generate some sshd activity to appear in the log by using ssh or putty, and confirm that you see a log entry on the correct log file that you’re monitoring due to the previous step.

13. Change /etc/ssh/sshd_config back, and restart the sshd service.

4.7 Writing to the logs from a script

At Managing Quotas, Red Hat recommends a daily cron job to touch /forcequotacheck so that quotacheck will be run during the next reboot. We will follow Red Hat’s advice because it exercises many of the concepts we’ve been studying: booting and init scripts, quotas, shell scripting, regularly run sysadmin jobs, and logging.

1. Let’s verify that the system init script actually does pay attention to the file /forcequotacheck.
   1. Determine what the system init script is: grep the /etc/inittab file for the sysinit action.

   2. Now, grep for forcequotacheck in that script. You should see two lines mentioning the forcequotacheck file. Run the command again, redirecting the output to assignment10/force_grep.txt

      $ wc force_grep.txt
        2  20 147 force_grep.txt

2. Try out the logger command:
   1. Use user.info as the “facility.level” pair
   2. Use testing as the tag
   3. Use I made this log entry as the message

3. Tail /var/log/messages to see your message from the previous step.

4. Write a script named assignment10/forcequotacheck.sh that takes no arguments and creates an empty /forcequotacheck file, as follows:
   1. Put our standard International script header at the top.
   2. Add argument checking. Print the standard error and usage messages and exit with a non-zero status if any arguments are supplied to the script.
   3. Write to the system log file using a logger command as follows:
      1. Use user.info as the “facility.level” pair for all logging messages in this script.
      2. Use the current script name as the tag for all logging messages in this script.
         • What variable should you use to get the script’s current name?
      3. Log the message: Attempting to force quota check upon next reboot

   4. Create the empty /forcequotacheck file using an if statement with the following structure:

      IF the creation of empty file /forcequotacheck is successful
         log a message "Successfully forced quota check upon next reboot"
      ELSE
         log a message "Failed to force quota check upon next reboot"

   5. Test your script with arguments to be sure the error messages work correctly.
   6. Test your script by running it as your sysadmin user without sudo
      • It should fail. (Why?)
      • Check the logs for the messages appropriate for this failure.
   7. Test your script with sudo so that it succeeds.
      • Check the logs for the messages appropriate for success.

5. Allow the system cron to run your script daily by copying your script file into the /etc/cron.daily directory.

4.8 Logrotate operations

1. Change your logrotate configuration file (in the /etc directory) to keep 5 weeks worth of backlogs by default. You will change exactly one character on each of two lines. Your wc and sum should be 33 99 619 and 62121 1.

2. Change your logrotate configuration file for the yum package (look for a logrotate-related directory under /etc for a yum-specific file) to rotate the yum logs monthy rather than yearly. Your wc and sum should be 7 12 101 and 38265 1.

4.9 Logwatch

1. Change the user that receives logwatch emails from root to your own sysadmin userid.

2. Change the detail of logwatch summaries from Low to Med (medium).

3. Use sudo -i to simulate a root login, and run the script /etc/cron.daily/0logwatch (cron does this daily, but you can do it too whenever you want).

4. Revert back to your sysadmin user, and if you successfully changed the user that receives logwatch emails, you should have an email from logwatch
   1. Run the mail command to view your email. (When you quit mail and you have looked at a message, it gets saved in ~/mbox which you can read with mail -f More details in man mail )
   2. At the &-prompt, type the number of an email message (probably 1)
   3. Use more commands (spacebar to advance a screen, /something to search for something, etc)
   4. Search for sshd to see mentions of sshd activity
   5. Type q to quit viewing a message
   6. Type q to quit the mail program and have the messages you viewed stored in ~/mbox

4.10 Process Accounting and Login History

1. Use chkconfig to find out what for which runlevels the psacct service is on. Put the output from the command you used into assignment10/psacct_levels.txt

   $ wc psacct_levels.txt
   1 8 58 psacct_levels.txt
   $ sum psacct_levels.txt
   60721     1

2. Turn on psacct for runlevels 2,3,4,and 5

3. Check the status of the psacct service, and start it if it’s not enabled.

4. Use the last command to view a listing of last logged in users
   • Create some login records for user100 by using ssh to login a few times: ssh user100@localhost
   • Once logged in, type a few commands such as date or who and then exit to log out again. Repeat once or twice.
5. Use the last command to select and view the last logins of only User 100, then run the command again, redirecting the output into assignment10/last_user100.txt

   • Do not use grep or any pipeline for this. One command. RTFM.

     $ tail -2 last_user100.txt | wc
     2 7 38

6. Use the lastlog to display a report of the most recent logins of all users

7. Use the lastlog command to select and view a two-line report of the logins for User 100 and then run the command again, redirecting the two lines into assignment10/lastlog_user100.txt

   • Do not use grep or any pipeline for this. One command. RTFM.

     $ head -1 lastlog_user100.txt | wc
     1 4 50

8. Run the ac command with the option to also print the individual totals (time totals) of the hours your users have been logged in. Run the command again, redirecting the output to assignment10/ac_individuals.txt

9. Run the lastcomm command to see all of the commands that have been run on your system since you enabled psacct and run the command again, redirecting the output to assigment10/lastcomm.txt

4.11 When you are done

When you are finished, run the Checking Program to create an overall mark. Submit the output to Blackboard in the correct location.

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. We 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. Optional: Keeping your base CentOS 5.8 VM snapshot, remove any intermediate snapshots you no longer require, to free up disk space.
   • Be careful not to remove your current work!

5.1 Part I - Fetch and Check

Do all the following steps on your CentOS 5.8 VM. Read through the whole list before you start typing anything.

1. Log in to CentOS as your sysadmin non-root account (same userid as Blackboard).
2. Create a directory in your sysadmin account named Assignments/assignment10 (exactly the same directory hierarchy as you already have on the CLS), unless you already have this directory.
3. Change to your above assignment10 directory.

4. As shown below, use wget to get a copy of the Fetch program from this URL into a file named do.sh: http://teaching.idallen.com/cst8177/13w/notes/data/assignment10wget.sh

   CentOS$ wget -O do.sh http://teaching.idallen.com/cst8177/13w/notes/data/assignment10wget.sh
   Saving to: `do.sh'

   Make sure you have a file named do.sh in your directory. You only need to download this once per assignment.

5. As shown below, use sudo and sh to run the do.sh script you just downloaded to CentOS with the USER environment variable set to your own CLS account userid (as stored in the USER variable).

   CentOS$ sudo USER=$USER sh do.sh

6. This Fetch program will connect from CentOS to the CLS using your account name. It will copy files from CentOS to your assignment10 directory on the CLS. It will then run the checking program on the CLS to check your work. You will need to answer one question about your IP address, and then wait and type in your CLS password.

It will look something like this:

CentOS$ whoami
abcd0001
CentOS$ hostname
abcd0001
CentOS$ pwd
/home/abcd0001/Assignments/assignment10
CentOS$ wget -O do.sh http://teaching.idallen.com/cst8177/13w/notes/data/assignment10wget.sh
Saving to: `do.sh'
CentOS$ sudo USER=$USER sh do.sh
---------------------------------------------------------------------------
abcd0001: FETCH version 1.  Connecting to CLS as USER='abcd0001' using ssh
---------------------------------------------------------------------------
abcd0001: Use local Algonquin IP cst8177-alg.idallen.ca [y/N]? n
abcd0001: Please wait; using ssh to connect to user 'abcd0001' on cst8177.idallen.ca ...
*** COURSE LINUX SERVER ***
abcd0001@cst8177.idallen.ca's password:         # enter your CLS password
---------------------------------------------------------------------------
idallen-ubuntu assignment10fetch_server.sh version 0 run by abcd0001.
Please wait; collecting info from abcd0001 Virtual Machine
---------------------------------------------------------------------------
VM files collected into Assignments/assignment10/abcd0001.tar.bz on CLS.
Now running check program for abcd0001 on CLS:
----------------------------------------------------------------------------
idallen-ubuntu check: Assignments/assignment10 check program version 00
*** Checking account for abcd0001 on idallen-ubuntu ***
[... checking program output appears here ...]

5.2 Part II - Check and Submit

When you are done with your assignment, you need to run the checking program one last time on the CLS and submit the output file, as follows:

Do all this on the Course Linux Server:

1. There is a Checking Program named assignment10check in the Source Directory on the CLS. Create a Symbolic Link to this program named check under your new assignment10 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.

2. Execute the above “check” program on the CLS 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. Some tasks 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 checking this assignment, and you like what you see on your screen, redirect the output of the Checking Program into the text file assignment10.txt under your assignment10 directory on the CLS. Use the exact name assignment10.txt in your assignment10 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.

4. Transfer the above assignment10.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.

5. Submit the assignment10.txt file under the correct Assignment area on Blackboard (with the exact name) before the due date. Upload the file via the assignment10 “Upload Assignment” facility in Blackboard: click on the underlined assignment10 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.)

6. Your instructor may also mark the assignment10 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!