Changes

OPS235 Lab 4 - CentOS7

1,634 bytes added, 18:20, 29 March 2015

no edit summary

== Part 1: The /etc/passwd file ==

# Look at the <code>/etc/passwd </code> file.

# Make note of the contents of that file.

# Read about the file: http://linux.die.net/man/5/passwd

{{Admon/note|Use centos1|Perform these steps in the '''centos1''' system.}}

# Read the man page for the <code>useradd </code> command.

# Create a new user account for each of your pod mates, using their learn account name as a user name. Give each user a password.

# Grep the <code>/etc/passwd </code> file for each of the new users.

#* What is the home directory of each user?

#* What group is each user in?

#* Where are the passwords stored?

# Look at the man page for /etc/shadow using the command man 5 shadow

#* Grep the <code>/etc/shadow </code> file for each of the new users.

#* Make note of this information.

# Create two new dummy users, <code>ops235_1 and <code>ops235_2</code>.

# Investigate the home directory of one of your new users.

#* What files are there? Be sure to include hidden files.

#* How does the operating system determine which files are created in a new home account? The answer can be found here: http://www.linuxhowtos.org/Tips%20and%20Tricks/using_skel.htm

#* Look at the files (including hidden files) in the template directory referred to in the article. Compare them to what is in a home directory for a new user. What do you notice?

#* Create a new file in this directory with the following command: <code>touch foo</code>#* Create a new user named <code>foobar</code>, with the option to automatically create a home directory.

#* Look at the contents of foobar's home directory. What do you notice?

# Be sure to record your observations in your lab notes.

{{Admon/note|Use centos1|Perform these steps in the '''centos1''' virtual machine.}}

# Read the man page for the <code>groupadd and <code>groupdel </code> commands.

# Note which option allows you to set the Group ID number (GID) when you create a new group.

# Examine the file <code>/etc/group</code>

#* Which values of GID are reserved for system accounts?

#* Which values of GID are reserved for non-system user accounts?

#* What is the lowest available GID number for non-system users?

#* What is the default group name of a new user?

#* Add a new group named <code>ops235 </code> with a GID of <code>600</code>.

#* You are angry at some irresponsible users on your system.

#** Add a new group named idiots.

#** Look at /etc/group and note the GID of idiots.

#** What GID is given to a new group if if you do not specify it?

#** Your anger has subsided. Delete the <code>idiots </code> group.

#** Look at /etc/group again and note the change.

{{Admon/note|Use centos1|Perform these steps in the '''centos1''' virtual machine.}}

# Read the man page for the <code>userdel </code> command. Note which option automatically removes the users home directory when that user is deleted.

# Delete the user ops235_1 using the command <code>userdel ops235_1</code>

# Delete the user ops235_2 using the same command with the option which removes the home directory of the user.

# Check the contents of the /home directory. What do you notice?

# Check the contents of the <code>/etc/group </code> file. What do you notice?

Be sure to record your observations in your lab notes.

# Add each of your new users to the group ops235 (in other words, add ops235 to each user as a supplementary group).

# Examine <code>/etc/group</code>. What has changed?# Use the usermod command to associate each of your pod mates' full name to their user name. With each change, examine their entries in the <code>/etc/passwd</code> file. What has changed?

# Be sure to record your observations in your lab notes.

<li>Issue the following Linux command:

<ul>

<li><code>runlevel</code></li>

</ul>

</li>

<li>Issue the following Linux command:

<ul>

<li><code>startx</code></li>

</ul>

</li>

<li>Issue the following Linux command:

<ul>

<li><code>service --status-all</code></li>

</ul>

</li>

<li>Note the services that are currently running.</li>

<li>Use the <code>service</code> command to stop the service named '''iptables'''</li> <li>Issue the <code>service</code> command to verify that this service has stopped.</li> <li>If you reboot now - the iptables service will be turned back on. We don't want it on though, it causes students headaches. To turn it off permanently we need to use the chkconfig command: <code>chkconfig iptables off</code></li>

<li>Reboot and confirm that it's no longer running.</li>

</ol>

Msaul

Administrators

13,420

edits

CDOT Wiki β

Changes

OPS235 Lab 4 - CentOS7

CDOT Wiki ^β