3.1 Searching the course notesIndex

The current 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.

3.2 The CLS Source DirectoryIndex

All references to the “Source Directory” below are to the CLS directory ~idallen/cst8207/14w/assignment12/ and that name starts with a tilde character followed by a userid with no intervening slash. The leading tilde indicates to the shell that the pathname starts with the HOME directory of the account idallen (seven letters).

You do not have permission to list the names of all the files in the Source Directory, but you can access any files whose names you already know.

3.3 Commands, topics, and features coveredIndex

This is a Users and Groups assignment. Review course notes Users and Groups.

Use the on-line help (man command) for the commands listed below for more information.

• chown – (change owner) Change the owner and/or group of an existing inode (needs root privilege)
• gpasswd – administer groups: set group administrator users, set group members, add and remove users from a group, change or remove the group password
• groupadd – add a new group to the /etc/group file
• groupdel – remove a group from the /etc/group file
• groupmod – modify group name, number, password account information in the /etc/group file
• groups – list the groups you (or another account) are in (from /etc/group)
• id [user] – display current account, current groups, and SELinux security context information
• newgrp – start a new shell with the permissions of a different group (similar to su)
• su [-] [user] – (substitute user) Become another user (default root), with that user’s permissions
• useradd – add a new user account and home directory
• userdel – delete an account (and possibly the home directory as well)
• usermod – modify account information (and possibly home directory as well)
• whoami – (who am I?) Display current account userid
• yum – install CentOS (Red Hat) software package

3.4 Correct user, command lines, and command outputIndex

• Parts of this lab are done as different non-root users. Other parts are done as the root user. Pay attention to which part is done by which user. You must use the su command to start a shell with the permissions of another user. The root user can use su to become any other user without requiring a password.

• If you start a root subshell, your prompt will tell you if you are the root user by changing to include a # character instead of a $ character. You can also use the commands id or whoami to show your current userid.

• Some answers require you to record command lines. Do not include the shell prompt with your command lines. Give only the part of the command line that you would type yourself.

• Make sure you know the difference between a command line (which is what you type into the shell) and command output (which is what the command displays on your screen). Pay attention to whether the question asks you to record the command line or the command output.

3.5 Backup and Recovery on CentOSIndex

1. Take a snapshot of your virtual machine before you begin each section of this lab so that you can recover back to the snapshot if needed.
   • You can delete the unused snapshots if everything works well.
   • CentOS snapshots are very small and fast compared to your Windows snapshots; you can save lots of them.
2. You may find it useful to also make a backup copy in a safe place of the /etc/passwd file and its shadow and the /etc/group file and its shadow on your CentOS system.
   • You can compare the old and new files using diff to know what has changed during this lab, and you can sometimes recover these files without reverting everything back to a snapshot.

3.6 Use a remote login, not the VMware consoleIndex

I recommend that once you have booted your CentOS VM, you connect to it and work using a remote login session (e.g. ssh or PuTTY) where copy-and-paste works and where you can have multiple simultaneous connections into the VM. The VMware console is not friendly.

Note that SSH sessions (and whatever you are doing inside them) do not survive across a VMware suspend. Make sure you save your editor files and exit your SSH session before you pause or suspend your virtual machine. (Editor sessions inside the VMware console do survive across suspend and resume.)

Advanced users may look into the various virtual terminal programs such as tmux and screen that do allow you to suspend and resume your sessions from a remote login.

4.1 Set Up – The Base Directory on the CLSIndex

1. 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.

2. Create the CLS directory ~/CST8207-14W/Assignments/assignment12

3. Create the check symbolic link needed to run the Checking Program, as described in the section Part II - Check and Submit below.

Run Part II - Check and Submit to verify your work so far.

4.2 CentOS: SnapshotIndex

0. Complete your CentOS Virtual Machine Installation and Verification.
   • Make sure it passes the checks for disk sizes and package counts.
   • Complete the critical system administration tasks required in Assignment #08.
1. Before you begin this assignment, create a snapshot of your CentOS Virtual Machine.
   • Enter a comment explaining where and when you took this snapshot.
   • You can restore back to this snapshot if anything goes wrong.

4.3 CentOS: Installation checkIndex

Review Package Management.

1. Install the man package, unless it is already installed.
2. Make sure man man works.
3. Install the mailx (note the spelling) package, unless it is already installed.
4. Make sure mail -V prints a version number.

Run the Fetch and Checking Program to verify your work so far.

4.4 CentOS: Creating a System Administrator AccountIndex

In this section you will create your own system administration account on your CentOS VM. This personal account can be customized for you. All work is done on your CentOS Virtual Machine.

Do not add extensive customization to the root account on a system, since such customization may not suit all root users of the system and may break automated programs that need to become the root user.

Leave the root account on your CentOS Virtual Machine alone.

References to man pages below will be to CentOS man pages, not CLS man pages. Since CentOS Linux and Ubuntu Linux are different distributions, they sometimes have different documentation and programs.

Review Users and Groups:

• The CentOS useradd command creates a new account, storing information about the account in the /etc/passwd file and about the account groups in the /etc/group file. It also creates a HOME directory for the account and places standard start-up files into it.

• The passwd command sets a password for an account, storing the password in the shadow password file named /etc/shadow. An account cannot be used until a password has been set. Group passwords (rarely used) are stored in the shadow group file /etc/gshadow.

1. Take a VMware snapshot that you can return to if things go wrong.
   • Enter a snapshot comment explaining where and when you took this snapshot.

2. If necessary, login to your CentOS Virtual Machine as the root user (the only user).

3. In the CentOS man useradd manual page:
   1. Read the SYNOPSIS syntax and note where the new LOGIN name must be used on the useradd command line. (It’s always the last thing on the command line.)
   2. Read about the --comment option and following argument used to define your full name. The (quoted) full name argument must immediately follow the --comment option on the command line. See below.
   3. Read about the Red Hat -r system account option and how using it will require you to use the -m option as well. Remember that.
      • The SYS_UID_* numeric identifier variables mentioned in the man page under -r are not actually defined in the given file – looks like a bug in CentOS.
      • The uid field for a system account will be less than the value of UID_MIN found in the file. Look up the numeric value for UID_MIN in the file; you will need it later.
   4. Read about the -m option. You must use this, too.
   5. You will need to use all three of the above options correctly. Do NOT place anything between the --comment option and the full name string that must follow it.
4. Following the SYNOPSIS syntax given in the useradd man page, add a new system account with the following settings:
   1. LOGIN: Use your eight-character College/Blackboard/CLS username.
   2. COMMENT: Copy and paste the exact text used for the fifth field of your own account line in /etc/passwd on the CLS:
      • The fifth field in /etc/passwd is called the GECOS field or user’s name or comment field.
      • The text you must copy and paste from the CLS and use as a comment field on CentOS is in the form: “Firstname Lastname - CST8207-14W-4NN” where Firstname and Lastname are your name and 4NN is your own three-digit lab section number.
      • Warning: Spaces are shell meta-characters.
      • Copy and paste all this information from your GECOS entry in the CLS password file to be the (quoted) argument immediately following the --comment option.
   3. Make sure the account is created as a system account with no password expiry.
   4. Use the option to create the HOME directory at the same time. (This option is required if you use the -r option.)
5. After creating your account with useradd, verify it:
   1. Search for the newly created account line in the password file:
      • Make sure it has the correct GECOS/comment/name field that should be a copy of the same field on the CLS.
      • To be a system account, the userid number for the account must be less than UID_MIN (from above).
   2. Run id abcd0001 where abcd0001 is your new account name.
      • Verify that the uid and gid are less than UID_MIN, indicating a system account.
   3. Make sure the newly created account also has a HOME directory created in the file system. Note that some default hidden files have been put into the HOME directory, copied from the directory /etc/skel. As system admin, you can put custom files in this directory that will be given to all newly created accounts.

6. If you didn’t succeed in creating the account and HOME directory correctly, with the correct comment (GECOS) and correct uid field, you may restore your snapshot and try again, or delete the account using userdel -r and try again.

7. Adjust the permissions of the new account HOME directory, if necessary, as follows:
   1. Set the permissions (mode) of the new HOME directory for your new account such that:
      • The owner (that is, you) can do everything
      • The group can search but not read or write
      • Other users can do nothing (no permissions)
8. Set a password for your new sysadmin account, as follows:
   1. Review the section “Choose a hard-to-guess password” in man passwd.
   2. Assign your new account a strong password that you can remember.
      • Make sure you assign the password to the new account; do not change your root account password. RTFM

   Warning: If you do not type the username argument to the password command, you are changing the password of the account that you are signed in with (i.e. the root account!). Do not change your root password! Change the password of your new non-root account.

9. Test your new account (from your current root shell):
   1. Run su --login abcd0001 where abcd0001 is your new account name.
      • No password will be required when run from root
      • This will start a login subshell with your account privileges.
      • You should see no error messages. Type some commands.
   2. Exit the su subshell, which will return you to your root login shell, with the # prompt character.
   3. Run ssh abcd0001@localhost where abcd0001 is your new account name.
      • Say yes to accept the new host key.
      • Enter your new sysadmin account password.
        • If the password doesn’t work, you probably changed the root password by mistake in an earlier step. Fix it and try again.
      • Upon success, you will be logged in as your sysadmin account through the SSH daemon and the localhost loopback.

      • Type who to see who is logged in. Your new account should be there:

        $ who
        root     pts/0        2013-11-16 00:35 (172.16.174.1)
        abcd0001 pts/1        2013-11-17 21:23 (localhost)

      • Exit this login session to return to your root login. (Your prompt should show the # character as root.)

For an interactive root subshell, your shell prompt should change from $ to include the # character that indicates root privileges.

Run the Fetch and Checking Program to verify your work so far.

4.5 CentOS: Using su to change accountsIndex

Now that you have your own sysadmin account on CentOS, always log in to your Linux machines using your non-root sysadmin account. Many servers actually disable direct login by the root user; you have to log in as the sysadmin user and then use su or sudo to run root commands. (We do not configure sudo in this course; wait until next term.)

When you start a root subshell using the su command, remember to exit your subshell to return to your previous account. Don’t keep layering and nesting multiple subshells inside one another by using su over and over. Remember to exit your su subshells.

4.6 CentOS: Set Up – The Base Directory on CentOSIndex

1. Log out from CentOS and log in to your new system administration account (not the root account!).
   • Always log in to your sysadmin account first.
   • Use su to become the root user if and when you need more permissions in any of the steps that follow.
2. Move your CentOS CST8207-14W directory from the root HOME directory to your own account HOME directory and recursively set its owner and group to be your userid and group.
   • You will need to use su to do this move and ownership change.
   • Remember to exit or suspend your su subshell after you are finished the move and ownership change. Do not continue using a root subshell.
   • Do not leave root-owned files in your account.
3. If not already done, create the same CST8207 assignment12 directory structure in your new sysadmin account HOME directory on CentOS as you have created on the CLS: CST8207-14W/Assignments/assignment12

This CentOS assignment12 directory is the base directory for all pathnames in this assignment. Store your CentOS files and answers here on CentOS.

Pay careful attention to whether you are working on the CLS or CentOS, and which account you are using! Watch the userid and hostname values in your PS1 prompt string! All answer files in this assignment get stored in the CentOS base directory, not on the CLS.

Run the Fetch and Checking Program to verify your work so far.

4.7 CentOS: No root files in non-root accountsIndex

Files saved anywhere under your sysadmin HOME directory in CentOS should be owned by you, not by root. (The presence of root files in non-root accounts is often a sign that your machine has been cracked!)

Do not leave root-owned files in your account. You should change the owner to you of anything you create as root in your account. To find files not owned by you in your account:

[abcd0001@abcd0001 ~]$ cd
[abcd0001@abcd0001 ~]$ echo "$USER"
abcd0001                                 # your own userid not abcd0001
[abcd0001@abcd0001 ~]$ find . ! -user "$USER" -ls
[... any non-abcd0001 files are listed here ...]

If you find any files, you should use the chown command to fix these files to be your own userid and group. (The command has a recursive option that lets you change everything under a directory.)

Advanced users can modify the above find to send pathnames into sudo running xargs with chown. See Find and Xargs.

4.8 CentOS: adduser and useradd are the sameIndex

Do the commands in this section using your own sysadmin non-root account. Use su only as needed. As mentioned above, all output files must be owned by you and saved on CentOS in the usual place for this assignment in your system admin account (not in the root account!).

On CentOS, useradd and adduser are the same command with two different names. On some versions of Linux – Debian, Ubuntu, etc. – adduser is a different command with different options.

1. On CentOS, try man adduser and then man useradd and see that they are exactly the same thing. (If the man command is not found, you missed a step in a previous assignment. Go back and install it.)

2. On the CLS (not CentOS), try the same two man command lines and see that the two commands useradd and adduser are different and have different man pages on the CLS. (The CLS runs Ubuntu Linux, which is a Debian-based distribution. CentOS is a Red Hat distribution.)

3. On CentOS, find the absolute pathnames of the two command names adduser and useradd. (Note: The which command won’t find the location of these two commands when run as a non-root user. Which other command locates the pathname and manual pages of a command name? Review the “related commands” in the Search Path notes.) You will need these two absolute pathnames for the next question.

4. On CentOS, save into output file adduser.txt in your CentOS base directory the two lines of output from a long ls listing of the two above absolute pathnames. Your file will be two lines, 20 words, and 130 or 135 characters.

Look at the ls output lines in adduser.txt:

• Do you see why useradd and adduser are the same command on CentOS?
• Do you see why the which command did not work to find the absolute pathnames of either of these commands when run as a non-root user? (Hint: Who has permissions to execute the useradd command?)

Run the Fetch and Checking Program to verify your work so far.

4.9 CentOS: The Simpsons Follies: homer and flandersIndex

You will need root privileges (e.g. via su) to run account management commands. Log in as your sysadmin account and then use su.

For this section you will require two more ordinary user (non-root, non-system) accounts. We will use two names from The Simpsons television series.

1. Create an account named homer (no options needed) and then give it a simple password.

2. Create an account named flanders (no options needed) and then give it the same password.

Run the Fetch and Checking Program to verify your work so far.

4.10 CentOS: The Simpsons Follies: documentationIndex

1. Use your sysadmin account. Do the commands in this section using your own non-root account. As mentioned above, all output files must be owned by you and saved on CentOS in the usual place for this assignment in your account (not in the root account!).

2. Use some id commands to record the account information for each of the two Simpsons accounts into a simpsons.txt file. Your file will be two lines, six words, 105 characters; one line for each of the two new Simpsons accounts.

3. Extract the account information lines for the two new accounts from the system password file and save the information in a simpasswd.txt file. Your file will be two lines, two words, 84 characters; one line for each Simpsons account. Each password file line will have seven colon-separated fields in it.

4. Put the long ls listing of the absolute pathname of each Simpsons account HOME directory (not the contents of the directory – just the directory itself) into a simpath.txt file, one per line. Your file will be two lines, 18 words, 119 or 125 characters. If you get permission denied, you aren’t using the correct option to ls to show only the directory, not the contents.

5. Put the three-digit numeric permissions of either of the above HOME directories in a simperm.txt file. Your file will be one line, one word, four characters. (Remember why three digits in a file is saved as four characters? Review Text file line end differences in File Transfer.)

Run the Fetch and Checking Program to verify your work so far.

4.11 CentOS: The Simpsons in the Public DirectoryIndex

The SB Output File: In the next steps, where you are required to save a command line or its output, do the command and then copy and record the command line or its output as a separate line into an output file named simpub.txt in your CentOS base directory that will be noted as the SB output file below. If you can’t answer a question, leave a blank line in this output file. (The vim option :set number may be useful to you as you edit.)

Below, we will create a /public directory in the system ROOT directory in which any user can create files. The directory will allow any user to create names in it (or remove names, or rename). Recall that the permissions on a directory are not the same as the permissions on the things named in the directory. Permission to change file names does not grant permission to change file content.

You will need to use a command that lets you start a subshell as another user. Review Users and Groups.

You need to run commands as different users. You may find it helpful to have separate windows open into your CentOS VM, with subshells in each window running as a different user. Then, you can simply change windows to change users instead of having to exit and enter subshells in the same window. Be lazy!

4.12 CentOS: The Simpsons one file multiple write permissionsIndex

You need to run commands as different users. You may find it helpful to have separate windows open into your CentOS VM, with subshells in each window running as a different user. Then, you can simply change windows to change users instead of having to exit and enter subshells in the same window. Be lazy!

1. Create a new empty file /public/homflan that has the owner and group of homer and homer.
   • Hint: You could log in as homer to create this file, or you could create the empty file as any user first, then use chown as root to change the owner and group.
   • Do a long ls listing of the file and verify that both the owner and group are homer.

2. As the flanders user try (and fail) to append the date to the /public/homflan file. You should get “Permission denied”.

3. As the homer user try (and succeed) to append the date to the /public/homflan file. There should be no error message.

4. Change only the file group and group permissions of the homflan file so that both homer and flanders can read and write the homflan file. Do not change anything in the system except the group and the group permissions of the file! Do not enable other write permissions! Do not create any groups or do anything other than change the file group and group permissions.

   Hint: homer, the owner of the file, will read and write the file using the owner permissions. Arrange that the file will be in one of the groups of the non-owner flanders and so group permissions will apply to flanders, allowing flanders to read and write the file using the group permissions. Other users will be neither the owner of the file nor in the group of the file, so other permissions will apply to them and they cannot write the file.

5. Test it as three users. Both homer and flanders should be able to append data to the file, while your sysadmin (non-root) account should not be able to append data.

6. Exit from all the Simpsons user subshells and return to your sysadmin account shell.

Run the Fetch and Checking Program to verify your work so far.

4.13 CentOS: Star Wars account managementIndex

The WA Output File: In the next steps, where you are required to save a command line or its output, do the command and then copy and record the command line or its output as a separate line into an output file name starwars.txt in your CentOS base directory that will be noted as the WA output file below. If you can’t answer a question, leave a blank line in this output file. (The vim option :set number may be useful to you as you edit.)

Take a snapshot of your virtual machine. Review Users and Groups.

1. Create an account named luke (no options needed).

2. Give the new luke account a simple password.

3. As your sysadmin account user (not root), run a long ls listing on the new HOME directory (just the directory, not the contents) of the new luke account. Only one line should output.
   • If you get permission denied, you aren’t using the correct option to ls to show only the directory, not the contents.
   • You should see one line of information about the directory itself. Save the one line as Line 1 in the WA output file in your CentOS base directory.

4. Search for lines containing luke in the four system accounting files (in the password and password shadow files and in the group and group shadow files – four files in total). When you see four lines of output, put them into a separate luke.txt file. That file should contain the four lines that contain luke in each line.

Run the Fetch and Checking Program to verify your work so far.

4.14 CentOS: Group management: The Megadeth ProjectIndex

• This section uses some commands you have not used before.

• Every command you need to use is mentioned in the opening page of this assignment document and is described in the lecture notes on Users and Groups. Become familiar with this list of commands before you continue, so that you know what command name to choose below. Every command also has a man page.

• You do not need to text-edit any files in this section. All the commands you need are noted at the top of this document (and again in the Users and Groups course notes). RTFM!

4.15 When you are doneIndex

That is all the tasks you need to do.

Check your work a final time using the Fetch and Checking Program and save the output as described below. Submit your mark following the directions below.

5.1 Part I - Fetch and CheckIndex

Do all the following steps on your CentOS Virtual Machine. Read through the whole list before you start typing anything. An example of what to type is given below the descriptions that follow.

Failure to read all the words will lock your account out of the CLS.

1. Log in to CentOS. Use your sysadmin non-root account (same userid as Blackboard) if you have created it, otherwise log in using the root account.
2. Create a directory named CST8207-14W/Assignments/assignment12 (use the same directory hierarchy as you already have in your own account on the CLS). If you have created your own sysadmin account already, create the above directory in the HOME of your sysadmin account, otherwise create it in the HOME directory of the root account. (This assignment will have you move it from the root account to your own sysadmin account anyway.)
3. Change to the above assignment12 directory (on CentOS!).
4. As shown below, use curl to get a copy of the Fetch program from the given URL into a file named do.sh. Make sure you have a file named do.sh in your assignment12 directory. You only need to download this once per assignment.
5. Warning: If you printed this page on paper, you may not be able to scroll right to read the whole web URL that you must pass to the curl program.

[assignment12]$ url=http://teaching.idallen.com/cst8207/14w/notes/data/assignment12do.sh
[assignment12]$ curl -A mozilla "$url" >do.sh
[... make sure you scroll right to read the full web URL above ...]
[... various download statistics print here ...]

[assignment12]$ fgrep -i 'error' do.sh    # make sure no errors (no output)
[assignment12]$ head -n1 do.sh            # make sure it's a shell script
#!/bin/sh -u

5. You must run the do.sh script you just downloaded. You must run the script as the root user with the USER environment variable set to your own CLS account userid. (Do not use abcd0001; use your own.) Failure to set the USER= variable as shown below will cause your account to be locked out of the CLS.

   If you have created your system admin account, you should use su to run the do.sh script, as shown in option b below. If you have only your root account created, you must run the script directly, as shown in option a below.

   Pick either a or b below (only pick one):

   1. Run the script directly as the root user: Use this only if you have not yet created your own sysadmin account:

      [root@abcd0001 assignment12]# whoami ; pwd
      root
      /root/CST8207-14W/Assignments/assignment12
      [root@abcd0001 assignment12]# USER=abcd0001 sh do.sh     # use your own userid, not abcd0001

   2. Run the script using su: Use this if you have already created your sysadmin account:

      [abcd0001@abcd0001 assignment12]$ echo "$USER" ; pwd
      abcd0001                                              # will be your userid, not abcd0001
      /home/abcd0001/CST8207-14W/Assignments/assignment12   # will be your userid, not abcd0001
      [abcd0001@abcd0001 assignment12]$ su -c "USER=$USER sh do.sh"   # must be double quotes, not single

   This do.sh script runs a Fetch program that will connect from your CentOS machine to the CLS using your account name in the USER variable. It will copy selected files from your CentOS machine to your assignment12 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, as shown below:

   ---------------------------------------------------------------------------
   abcd0001: FETCH version 3.  Connecting to CLS as USER='abcd0001' using ssh
   ---------------------------------------------------------------------------
   abcd0001: Use local Algonquin IP cst8207-alg.idallen.ca [y/N/?]? n
   abcd0001: Please wait; using ssh to connect to user 'abcd0001' on cst8207.idallen.ca ...
   *** COURSE LINUX SERVER ***
   abcd0001@cst8207.idallen.ca's password:         # enter your CLS password
   ---------------------------------------------------------------------------
   idallen-ubuntu assignment12fetch_server.sh version 6 run by abcd0001.
   Please wait; collecting info from abcd0001 Virtual Machine
   ---------------------------------------------------------------------------
   VM files collected into CST8207-14W/Assignments/assignment12/abcd0001.tar.bz on CLS.
   Now running checking program for abcd0001 on CLS:
   [... checking program output appears here ...]

5.2 Part II - Check and SubmitIndex

When you are done with your assignment, you need to run the checking program one last time on the CLS (not from CentOS) and submit the output file, as follows:

Do all this on the Course Linux Server when you are ready to submit:

1. There is a Checking Program named assignment12check in the Source Directory on the CLS. Create a Symbolic Link to this program named check under your new assignment12 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.

2. 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 fetched CentOS 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.)

   Remember: The checking program does not fetch new files to the CLS from your CentOS VM. You must run the Fetch program on your CentOS VM to update the fetched files on the CLS so that the checking program can mark them on the CLS.

   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.

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 assignment12.txt under your assignment12 directory on the CLS. Use the exact name assignment12.txt in your assignment12 directory. Case (upper/lower case letters) matters. Be absolutely accurate, as if your marks depended on it. Do not edit the file.
   • Make sure the file actually contains the output of the checking program!
   • The last text line of the file should begin with: YOUR MARK for
   • Really! MAKE SURE THE FILE HAS YOUR MARKS IN IT!
4. Transfer the above assignment12.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.
   • Make sure the file actually contains the output of the checking program!
   • The last text line of the file should begin with: YOUR MARK for
   • Really! MAKE SURE THE FILE HAS YOUR MARKS IN IT!

5. Upload the assignment12.txt file under the correct Assignment area on Blackboard (with the exact correct name) before the due date. Upload the file via the assignment12 “Upload Assignment” facility in Blackboard: click on the underlined assignment12 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 need to comment on any assignment submission, send me email.

   You can upload the file more than once; I only look at the most recent. You must upload the file with the correct name; 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 submissions.
   1. Verify that your latest submission has the correct 16-character, lower-case file name beside the Attached Files heading.
   2. The Submission Field and Student Comments headings must be empty. (I do not read them.)
   3. Save a screen capture showing the uploaded file name. If there is an upload missing, you will need this to prove that you uploaded the file. (Blackboard has never lost a file.)

   You will also see the Review Submission History page any time you already have an assignment attempt uploaded and you click on the underlined assignment12 link.

   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!

• 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!