Linux+
In which file are user accounts stored?
/etc/passwd
In which file are hashed passwords stored?
/etc/shadow
What standard directory contains system logs?
/var/ or, more specifically, /var/log/
What are the three requirements for mounting a file system?
1) A device (/dev/sdb1, for example) 2) A directory (mount point) 3) Root/
Explain the three general steps in orchestration.
1) Administrators create a set of instructions or configurations. 2) The orchestration tools deliver the instructions and configurations to client systems. 3) The orchestration clients process the instructions
A group with a shared directory set up by another administrator is having several problems with permissions in that directory. You've been asked to investigate. Which commands can you use to check existing permissions to help assess the current setup?
1) ls -al 2) getfacl 3) lsattr —These commands will give you a good perspective on permissions, ACLs, and any attributes that have been set
What are the steps required to grow the file system /dev/data/ datastore1 from its current 200 GB size to 400 GB?
1) sudo umount /dev/data/datastore1 2) sudo e2fsck - f /dev/data/datastore1 3) sudo lvextend -L400G /dev/ data/datastore1 4) sudo resizefs /dev/data/datastore1 5) sudo mount /dev/data/datastore1 /data1
Which command can you use to create a new volume group, shared, with /dev/sdb1 and /dev/sdd1? And then how do you view your volume groups?
1) vgcreate shared /dev/sdb1 /dev/sdd1 2) vgdisplay
What is the IP address associated with the loopback address?
127.0.0.1
What IP address range is associated with link-local/APIPA addresses?
169.254.x.x
What is the base version of your currently running kernel according the uname command?
3.10
What is the generic format of the /etc/fstab file?
<Device or UUID> <Mount point> <File system type> <Mount option> <Dump option> <fsck option>
Which of the following symbols indicates the start of a comment in Bash scripting?
#
What is a software dependency?
A software dependency is one or more software packages that must be installed before a desired package is installed.
Why would you need to change the locale settings of a system based on its global location?
A system's locale determines how it will represent various culture-specific elements, the most prominent of which is the language used in the interface. However, a locale can also determine factors such as how date and time are formatted, how monetary values are formatted, and more.
Mobile devices have created a mobile workforce. Your users need to be able to connect to the corporate network to access shares, printers, and other internal tools. Which service can you set up to enable secure connectivity for your mobile users?
A virtual private network (VPN) service works well because it encrypts all data between the user's device and the corporate network.
One of the other system administrators on your team states that a process is now a zombie. What is the characteristic of a zombie process that makes it a problem for administrators?
A zombie is a process that was terminated, but has not yet been released by its parent process. It is in a "zombie-like" state where it cannot accept a kill signal because the process isn't available anymore.
What final task do you need to complete in mounting a new file system to have that new file system mount at boot time?
Add its entry to the /etc/fstab
In the monolithic kernel vs. microkernel debate, Linus Torvalds chose a monolithic kernel for Linux. Why?
Although a monolithic kernel is larger than its microkernel counterpart, the tradeoffs for running system modules, device drivers, and file systems in kernel space, and overall speed, far outweigh
To move to a public cloud offering for your company's applications, you respond with the recommendation of using one of the two primary cloud service provider (CSP) companies. What are the two primary CSP companies from which to choose?
Amazon (Amazon Web Services) and Microsoft (Microsoft Azure).
Ansible is a very popular orchestration tool in both large and small company networks. How does Ansible deliver configuration files to nodes?
Ansible delivers files over SSH connections using an agentless solution.
Give examples of open source orchestration tools used in enterprises.
Ansible, Puppet, Chef, Kubernetes, and OpenStack are all examples of open source orchestration tools.
Chris Mason, a sales executive at Develetech, has been told to connect to a particular server to access resources. He has asked you for help because the instructions indicate he should connect by IP address. He cannot easily remember the IP address and has asked you if there is an easier way to connect to the server. What service can you use to make the connection easier for Chris?
Answers may vary, but DNS is a good choice because it centralizes and streamlines the name resolution process.
As far as the hardware, what else do you need to consider before you can install Linux on these systems?
Answers will vary, but might include ensuring that System A's video card is supported by the Linux distribution you plan to install; and generally ensuring that all hardware components have adequate driver support in the Linux kernel.
What is your preferred method for getting help with Linux, and why?
Answers will vary. Some prefer man pages because they are quick and easy to access at the command-line, whereas other documentation may require Internet access and a web browser. However, it can be difficult to understand the true power of some utilities just by reading their man pages, so some students may prefer to consult online documentation that goes into more detail and/or provides practical examples. Other students may prefer to engage the Linux support community directly, as that interactive component is often necessary in addressing complex, open-ended questions.
You are deploying four Debian-based Linux servers and you do not want to use SELinux for access control. What is the most common alternative to SELinux for Debian-based systems?
AppArmor is the most commonly used alternative to SELinux for Debian-based systems.
Where can you, as a user, switch to a different graphical user interface (KDE to GNOME, for example)?
At the graphical login screen.
Why do we use a service such as DNS to map IP addresses to names?
Because IP addresses are difficult to remember, and names are easier for humans to remember.
Why is encryption essential to secure communications on a system or over the network?
Because only someone or some process with the proper key can decrypt the information, which makes captured
Which authentication method would you use if you didn't want to issue hardware tokens, install special software, or require passwords of your users?
Biometrics is one such authentication method. The user's physical characteristics, such as retina, fingerprint, or voice, are used in place of passwords, tokens, or specialized software.
Which of the following boot options enables users to mount a file share as the root file system, rather than storing that file system locally?
Boot from NFS
Four of Develetech's server and development systems are listed below. Identify which package manager is appropriate for each of them.
CentOS Web Server RPM, as CentOS is derived from Red Hat Linux. Ubuntu Development Workstation dpkg, as Ubuntu is derived from Debian. Raspberry Pi with Raspbian Linux dpkg, as Raspbian is derived from Debian. Scientific Linux RPM, as Scientific Linux is derived from Red Hat Linux.
You need to install the Apache web service on your new CentOS web server farm and you cannot decide between using a package manager and compiling. You look at both options thoroughly and decide that, for your current needs, installing via package manager will be adequate. Which package manager do you use to install Apache?
CentOS is a Red Hat Enterprise Linux derivative and YUM is the preferred package manager to use.
What must a user do in a shared directory to ensure that each group member has full read and write access to files they create?
Change the group ownership to the group: chgrp accounting salaries.txt —The user doesn't have to be root or use sudo to change group ownership because the file creator is the file's user and group owner,
You are exploring your local (shell) variables on each system that you manage. The first variable you check is the SHELL variable. How can you check the SHELL variable and what do you expect it to display?
Check the SHELL variable with echo $SHELL and expect /bin/bash as the output.
Jerry Robinson received an access denied message on a file. He told the service desk that the user permissions indicate the owner has read access. What suggestion would you make to address the issue?
Check to see if Jerry Robinson's account is the owner of the file, and if not, make him the owner if he should be.
List the address ranges for Class A, Class B, and Class C IP addresses.
Class A = 0.0.0.0-127.0.0.0;
List the default subnet mask for Class A, Class B, and Class C IP addresses:
Class A = 255.0.0.0 or /8; Class B = 255.255.0.0 or
There are two device types recognized by the udev device management system: coldpluggable and hotpluggable. When does the system load modules for each device type?
Coldpluggable device modules are loaded at boot and hotpluggable device modules are loaded dynamically by the kernel when a new device is plugged
OpenSSL is standard on Linux systems and is useful for securing data. What are some of its common uses?
Common uses include: generating public and private keys; generating self- signed digital certificates in various formats; generating digital certificates for other entities based on CSRs; calculating hash values using various functions; encrypting and decrypting data using various algorithms; and managing keys and certificates in a CA.
You and the other system administrators have a maintenance partition, / maint, that you only want mounted when required for administrative activities. How can you use the file system only when you need it?
Don't make an entry for /maint in the /etc/fstab file. Only mount the file system when you need it and then unmount it when finished.
You want to manually install Linux on a new laptop that has no DVD drive, and you do not have access to one. How can you install Linux onto the laptop?
Download the ISO and use a utility to write the ISO to a USB thumb drive. Then, boot from the thumb drive.
Develetech employees have contacted the help desk because they cannot connect to a particular server. Part of your investigation indicates the server has been configured with a dynamic IP address. How could this contribute to the problem and what steps should be taken to address it?
Dynamic IPs could change, meaning the server's identity on the network has changed, keeping users from connecting to it. A solution is to use a static IP address configuration.
You're assisting a group of web developers to set up their test systems, but you don't want other users to know about them, so you aren't registering them with your network DNS servers. Instead, you're helping the developers edit a local file on their systems that will act as a local IP address-to-name mapper. Which file can you edit for this private name resolution service?
Edit the /etc/hosts file on each developer's workstation to map the test systems' IP addresses to names.
You are researching a possible breach attempt on one of your SELinux- protected systems. Which command can you use to check the SELinux auditservers and log?
Either the sealert command or the audit2why command will provide you with results.
Depending on the Linux distribution you have chosen to install, which accounts are you prompted to set up during installation?
Every distribution prompts for a user account and some prompt for the root password as well. CentOS, for example, prompts for a user account and the root password.
List at least five application-layer protocols.
Examples include: HTTP, HTTPS, SMTP, SSH, Telnet, FTP, TFTP, SNMP, DNS,
There are several automated processes that copy files between servers for backups. These processes use the standard File Transfer Protocol (FTP). What is wrong about using FTP, and what is the better alternative?
FTP data is transferred in plaintext (no encryption). The better alternative is Secure File Transfer Protocol (SFTP), which is encrypted.
True or false? According to the uname command, you are running a 32-bit hardware platform.
False.
True or false? Arrays start with the index 1
False.
True or false? Linux supports a unique set of device standards, and devices that work on other operating systems will usually not work with Linux.
False.
True or false? A graphical desktop environment is required for most administrative activities, such as creating new users and installing new software.
False. In fact, in most enterprises,
True or false? In Linux, Equipment.txt and equipment.txt refer to the same file.
False. Linux file names are case-sensitive. These are two different files.
True or false? Using a dot at the beginning of a file name makes the file more secure.
False. The file is hidden from normal view as a matter of organization, but does nothing for security.
True or false? There is a limit to the number of conditions in a case statement.
False. You can have as many conditions as necessary.
What is the purpose of file globbing in scripts?
File globbing, such as defining a list of files as *.sh, is a shorthand method of defining a list of files with
What is the human-readable name of a network device?
Hostname
What is the name of the logical address used by the TCP/IP protocol suite?
IP address
What is the bit length of IPv4 addresses?
IPv4 addresses are 32 bits in length.
What is the primary architectural difference between the X and Wayland display servers? How does this difference affect performance?
In X, the compositor is separate from the display server. In Wayland, the compositor and display server are one. The Wayland compositor can therefore interact directly with clients, minimizing latency.
Your company has standardized on CentOS as the corporate Linux distribution. You want the greatest amount of control over how programs are installed, where they are installed, and all install options. Which install method works best for your requirements?
Installing from source gives administrators the greatest amount of control over
What is the role of the MBR?
It contains the partition tables, determines the currently active partition, and determines which partitions are bootable.
In a YUM repository configuration, what does the gpgcheck=0 entry do?
It disables GPG checking for the repository.
What does the ./configure command do?
It gathers system information needed by the application to be compiled and stores it in the makefile.
What type of device is /dev/sdb?
It is a storage device such
Which of the following accurately describe the user space?
It is the area of memory in which most high-level software runs, and It is the area of memory in which background processes and low-level systems libraries run
You have set up a training session for new Linux system administrators and you are discussing log files, their format, their location, and their contents. Generally speaking, where are most Linux system logs located?
Linux system logs are located in the /var/log directory.
You need to know which file systems are supported by one of your Linux systems. How can you find out?
Look at the /proc/filesystems file to see
What is the name of the physical address used in Ethernet networking?
Media access control (MAC) address, permanently set on the network interface card (NIC) by the manufacturer.
What is a common source of problems with keyboards, printers, and storage adapters?
Missing or poorly configured drivers are a common source of hardware problems. 2. What is the term used to describe the situation where a process
One of the most important qualities of the Linux kernel is that it is modular. What does this feature do for Linux as a whole?
Modularity enables users to configure and extend the kernel's
What is one disadvantage of a monolithic kernel compared to a microkernel?
Monolithic kernels are larger and consume more RAM.
What are the two components of an IP address?
Network
Which of the following is a computer bus standard used by high- performance NVMe solid-state drives (SSDs)?
PCIe
You're editing a file in Vim and you realize that you've made several errors and decide to start over with your editing. How do you leave the file without saving any changes that you've made?
Press Esc to enter command mode and
You've created a script in Vim and note that you haven't entered any instructions or documentation into the file. Standard practice is to add your comments above the line of code that you're describing. How do you open a new line above the one you're currently typing on?
Press Esc to enter command mode and then press O.
How do you copy and paste text in the Vim editor?
Press Esc to enter command mode, then type y for yank (copy) and then p for paste.
What is the common package manager and package management utility for Red Hat-derived distributions?
RPM and YUM, respectively.
Name the three types of Linux user accounts.
Root user (superuser), standard user, and service.
Which of the following hardware connection technologies is primarily used in enterprise storage because of its fast speeds and high reliability?
SAS
Which function is associated with the SCI layer of the kernel?
Sending service requests to the kernel
Email is an essential network service. Which programs might you select for setting up email services on your Linux server?
Sendmail or Postfix are common Linux
Your team determines that for certain systems, snapshots are the appropriate backup method for critical storage contents. What is the advantage of a snapshot?
Snapshots can be taken as checkpoints that you can restore to a particular point in time if required.
What type of firewall examines network packets in isolation, rather than in the context of other packets in a transmission?
Stateless (packet filtering)
Why is it important to put the principle of least privilege into practice?
System security is greatly enhanced by only granting users the minimum amount of rights and permissions they require to perform
You've taken a new position as a Linux administrator and you discover that every Linux system contains a /boot/efi/ directory. What is the significance of this /boot/efi/ directory?
Systems with the /boot/efi/ directory use the UEFI boot process rather
What is the primary difference between the .bashrc and the .bash_profile files?
The .bash_profile file is executed upon first login to the system, and .bashrc is executed upon subsequent logins.
Which directory or file system is a likely candidate on which to impose storage quotas on a shared Linux system?
The /home directory or file system because users tend to store everything without regard to space used.
You're a new system administrator and you might not know all the commands to find out every detail about a Linux system. Although you don't know the commands, where can you go on the file system to find out the same information in text file format?
The /proc file system contains text files that hold process information, hardware information, kernel parameters, modules, and
Which online documentation site provides a comprehensive resource for Linux documentation including manual pages, FAQs, HOWTOs, and other types of documentation?
The Linux Documentation Project
Your CIO has tasked you with the job of finding an appropriate cloud service to host some of your applications. The application needs to appear as if it is locally installed. Which cloud model will you select?
The Software as a Service (SaaS) offering is the appropriate choice because your CIO has tasked you with the definition of SaaS itself—applications are hosted,
What happens if you issue the following command? mail [email protected] < addresses.txt
The addresses.txt
You have tasked a junior administrator with adding a single boot loader option to three of your Linux systems. The administrator lets you know that he was unsuccessful at making the changes because he received a permission denied error. What is the issue?
The administrator must have superuser privileges to create a new GRUB 2 custom menu file.
How can you remove an entry from the at command queue?
The atrm command can be used to delete a scheduled
What is the purpose of using a chroot jail?
The chroot jail isolates or confines a process or program to its own directory structure. The process cannot live or access anything beyond the isolated chroot location (directory).
A user complains that a script that she created and has full access to (rwxrwx---) is not executing for her. What is the problem with this script?
The execute bit was removed from the script by the ACL. It's possible that the script consumed too many resources and an administrator likely removed
You have seen other administrators use the export command and you have seen it referred to in documentation for scripts. What does the export command do?
The export command changes a local (shell) variable into a global
As an administrator, you've created a shared directory and made the necessary permissions changes to allow a group of users access to that directory. You've also added users to the group. When a user (susan) who is a member of the group creates a file in the
The file's user and group
Your parent company purchased another smaller company that has six Linux systems in its server room, all of which are now your responsibility to manage. They all run the firewalld service. Which command can you use to manage the firewalld service and its associated zones?
The firewall-cmd command enables you to configure firewalld by querying, adding, modifying, and deleting
During installation, you are prompted to set up a system's networking identity. What information is included in a system's networking identity?
The hostname, IP address information, and DNS servers. Most networks, especially corporate ones, have DHCP servers that provide the IP address and DNS information.
You notice several files in your home directory under the .ssh directory. One of them is id_rsa.pub. What is this file's purpose?
The id_rsa.pub
You have downloaded a new kernel module that you want to load into your running system's kernel. You do so using the insmod command. You checked, and the kernel module is in the list of loaded modules, but it isn't working. What might have gone wrong?
The insmod command loads only a specific module and does not load any dependent modules. It's likely
Which command actually compiles the source code into executable code?
The make command compiles
What does the make install command do in the software compilation process?
The make install command copies the compiled binaries to the
What is the final step in compiling software?
The make install command is the final step.
You have downloaded, decompressed, and extracted a software program tarball, and run the ./configure command. What is the next step in the installation process?
The next step is to run the make command.
Your team is setting a standard for the /etc/nsswitch.conf file. After some debate, the team decides to use the preferred configuration for the ordering of name lookup services. What order is this?
The preferred configuration is /etc/hosts
The Performance and Capacity Team in your company requires a system activity report on one of your Linux systems. The team contact has requested a CPU report. Which command can you issue to gather the information for the report?
The sar -P ALL command gathers CPU statistics for all CPUs.
Describe the difference between using the su command and using the sudo command to perform administrative tasks.
The su command enables an authorized user to become the root user by switching to the root user account in a complete root-owned shell. This is handy for the administrator but very dangerous because of the potential for human error. The sudo command enables an authorized user to issue individual commands as the root (or other user), limiting potential damage to the system.
What condition does the while loop test for?
The while loop tests for true conditions.
The hostname, IP address information, and DNS servers. Most networks, especially corporate ones, have DHCP servers that provide the IP address and DNS information.
They use an automated orchestration suite that distributes a pre-configured system image to the hardware.
What is the purpose of creating a centralized internal repository?
This centralized approach makes version control much simpler.
What does the iostat /dev/sda command do, and how can it be useful in troubleshooting?
This command generates read and write statistics for the /dev/sda block storage device. It can be useful in troubleshooting because it can help you monitor storage usage statistics and
What are the two transport-layer protocols?
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
True or false? IP forwarding is the Linux kernel implementation of network routing functionality.
True.
Your coworkers are trying to decide between using UEFI or legacy BIOS for some of your systems. They ask you for your opinion. What are the advantages of UEFI that you can tell your coworkers?
UEFI is faster, can address a larger amount of memory, can access huge drives, can use more hardware types, and has improved
You want to set some very restrictive protection on certain executables. AppArmor gives you that capability. Which mode do you use for the most restrictive profiles for your executables?
Use enforce mode because it logs violations and prevents any violations from occurring.
Which command can you use to display information about all block devices and how can you find out more information about each device in the list?
Use lsblk to list all block devices and their parent devices. Use udevadm info to display specific information about
You have written a log file for a script that you run to gather output, but each day the output gets overwritten. Which operator can you use to append rather than to overwrite the log file?
Use the >> append operator to add data to the end of the file each day.
You recall that a few days ago, you ran a command that helped you find a filtered list of files on the file system. You don't remember the command's somewhat complex syntax. How can you reproduce the command without searching the Internet for the correct syntax again?
Use the Up Arrow key until you find it and then press Enter to execute it. The Up Arrow key scrolls back, one command at a time,
You have added several jobs to the at queue and you need to check the status. How can you check the at queue?
Use the atq command.
As the root user, you need to check all scheduled tasks that belong to root. How can you check them?
Use the crontab -l command to
You believe either that the PATH variable is incorrectly set or that there are a significant number of commands missing from the system. How can you display the PATH variable value?
Use the echo $PATH command.
You loaded a kernel module that has caused your system to become unstable. How do you remove the errant module?
Use the rmmod command.
You have a CentOS system that runs an application for your company, but anyone who runs it receives errors, as if some critical parts of the application were missing. How can you verify the application's components?
Use the rpm -V <application name> command to verify that all components of the application are installed.
From where does the lsdev command pull its displayed information?
What is a common source of problems with keyboards, printers, and storage adapters?
Bob opens a ticket stating that he receives a permission denied error when trying to cd into /opt/Finance. Bob is a member of the FinanceDept group. What is the problem with Bob's access?
While Bob is part of the FinanceDept group and can access all other FinanceDept group assets, he cannot use /opt/Finance because
Which of the following wireless connection standards is primarily used to create a local area network (LAN) for home and office computing?
Wi-Fi
Why would an administrator need or use console redirection?
Without an operating system on the hardware, an administrator needs some method of connecting to a "bare metal" system. Console redirection
What are some examples of changes you could make to the default GRUB 2 menu?
You could change options such as how many seconds GRUB 2 will wait before automatically selecting the default boot option; whether or not GRUB 2 will order kernel versions in a sub-menu; whether or not GRUB 2 will display the menu in a graphical terminal; etc.
You created a new partition, /dev/sdb1, created the file system (XFS), and mounted the file system as /Files. You also created a few directories on / Files for various groups within your organization as shared file spaces. After a maintenance reboot a few days later, users are complaining that their directories and files that you set up no longer exist. What is the problem?
You didn't make an entry for the new partition in /etc/fstab, therefore, the file system didn't mount on boot.
You need to add an administrator to the /etc/sudoers file to give them the ability to use the sudo command. Which command must you use to add users to the /etc/sudoers file?
You must use visudo since you cannot edit the /etc/sudoers file directly with Vim or other text editors.
If you cd into /opt/log/first/test/test1 and then type cd ~ and press Enter, which directory is now your current working directory?
Your home directory. If your user name is bsmith, this is /home/bsmith. The cd ~ command returns you to your home directory regardless of where
Linux users use the cat command to print a file's contents to the screen, but the original purpose of cat is to concatenate or join the contents of two or more files together into a single file. You have files test.1 and test.2 that you want to combine into a single file, test.3. How can you accomplish this using cat?
cat test.1
What command is equivalent to issuing chown :mygrp file1?
chgrp mygrp file1 —Both commands change the file's group to mygrp without changing the
You have two files that contain more than 100 lines of text each. You need to compare them because, while they're supposed to be similar, checking each one against the other is time-consuming. Fortunately, Linux has a utility to compare the two files. How can you compare file1.txt and file2.txt using this utility?
diff file1.txt file2.txt
What does the lpq -a command display?
displays print jobs on all configured
You believe that the network interface card is failing on one of your servers and you need to get the specifics of it so that you can replace it with the same product. Without going to the data center and opening the server's case, how can you find the network card's details?
dmesg | grep -i network
Which of the following commands is an often unreliable way of querying the system for attached hardware components?
dmidecode
What is the common package manager and package management utility for Debian-derived distributions?
dpkg and APT, respectively.
A user asks you to help him find a particular string ("audition") in a file, actors.txt. He can't seem to remember which actor he had auditioned for a commercial spot, and he needs to call her back. How can you find his actor using a simple command, rather than read the text file manually?
grep audition actors.txt
Your company is global in scope and you have systems in data centers in several different countries. Often while typing you discover that some odd characters appear on the screen. One of your counterparts in one of the offshore countries informs you that they have changed the keymap to better suit their needs. How can you change the keymap for U.S. compatibility?
localectl
You want to check the print queue before you attempt to reboot the system. How do you check the print queue for the non-default printer, HPLJ5?
lpq -P HPLJ5
Several users have been issuing multiple print jobs to the printer, causing it to become backed up and unresponsive. You enter the lpq command to query the print jobs, and notice that one job is very large and likely causing the bottleneck. Which of the following commands should you enter to stop the offending print job and free up the queue?
lpq -s {print file name}
How do you send the file students.txt to the HPLJ5 printer?
lpr -P HPLJ5 students.txt
Multiple users have complained about file access in a shared directory, but you've checked your daily backup reports and there are no corrupt files. Which command can you issue in the directory in question to investigate the problem further?
ls -l —This command displays the permissions of all files in the directory to help you sort out the problem. It's
A coworker sends you an instant message and asks you how to appropriately format a manual page for the mv command so that she can send it to the printer and get readable output. What command can she enter?
man -t mv
One of the developers has told your manager that he needs the file system / code rebuilt using the XFS file system type. Which utility can you use?
mkfs.xfs
Diane Smith has left the company and you want to preserve her home directory, so you decide to rename it. How can you rename /home/ dsmith to /home/dsmith.keep?
mv /home/dsmith /home/dsmith.keep
Which of the following is the correct way to assign a variable in Bash scripting?
my_name = 'Mary'
How would you create a file with the following content using a single command? Note that each component should be on its own line (a total of three lines), like addressing a letter in the mail: Bob Jones 222 Main Street Dallas, TX
printf "Bob
The Linux system that controls your phone system has experienced some problems with memory lately, and you're curious as to what the problem is. Upon further investigation, you note that the system is fully updated and patched. You decide to check running processes to determine if something has gone awry with one of the services. Which command can you use to check running processes?
ps
How can you create a physical volume on /dev/sdd1?
pvcreate /dev/sdd1
Which command enables a user to log in to a system with their own credentials, and then to become the root user to perform administrative tasks?
su —The su command enables an authorized user to become the root user.
What is the SysVinit equivalent of systemctl enable httpd.service?
sudo chkconfig
Another system administrator appears in your cubicle and asks you to display storage devices and their file systems on server05. Which command can you use to show him the info he needs?
sudo lsblk -f
You are teaching a junior administrator how to install software via YUM. You ask him to install the Lynx text-based web browser (lynx) on a test system. What should the install command look like?
sudo yum install lynx
How can you start the CUPS service?
systemctl start cups
You've had several complaints about the performance of one of your systems. You log in and find that it responds slowly to commands. You want to look at processes that might be consuming too many resources. Which command can you use?
top
When the boot loader completes its tasks, what happens next?
transfers control to the kernel.
As an administrator, it is one of your jobs to keep track of the kernel versions on your Linux systems and attempt to be consistent where possible. Which command can you run to see the kernel version?
uname -r returns the kernel's major and minor version numbers, making it easier to compare versions across many systems.
What are the three commands used to properly edit the /etc/passwd file?
useradd, usermod, and
You tried using locate to find the cat command but locate searches for strings and returned more than 2,000 hits. You need something more efficient for searching for a specific file, especially commands. Which command can you run to selectively find the cat command?
which
You know that for ext4 file systems, you use the resizefs utility to grow the file system, but which utility can you use to perform this same action on XFS file systems?
xfs_growfs
A junior system administrator asks for your help in determining which components make up the Linux server he's working on. He needs to know brands, models, and other details of certain components to buy replacement parts. To which command or file(s) can you direct him?
He should run the dmesg command to see a complete list of all attached hardware components and their details.
What are two common hardware-related issues that are not a result of faulty drivers or insufficient memory?
Loose or damaged cables and improperly slotted or plugged devices.
While investigating complaints of system "slowness," you use the top command, but aren't seeing any issues from a CPU usage standpoint. You want to check memory usage while still using the top command. Which command key can you use to display processes by memory usage?
M (uppercase).
You need to set up a VPN so that your users can securely connect to the corporate network on public Wi-Fi connections, from home networks, and from any location where they have Internet access. Which software can you investigate that supports password, certificate, and smart card authentication methods?
OpenVPN is a good choice
Why does the following command send the name Sally Davis to the sally.txt file? echo "Sally Davis" > sally.txt
Because the echo command, coupled with the redirect operator (>), redirects stdout, Sally Davis, to the sally.txt
Why do you need to assume root privileges when running the make install command?
Because the make install command writes to system directories that only root has permission to
You need to create a new volume for Human Resources. That group has purchased a new 1 TB drive for their volume. What is the first step in the process of creating the logical volume?
Create a partition using fdisk or a similar tool.
What task can you perform to be able to refer to a device with the same custom name every time it is plugged in?
Create a symbolic
You are researching a possible breach attempt on one of your SELinux- protected systems. Which command can you use to check the SELinux audit log?
Either the sealert command or the audit2why command will provide you with results.
Which of the following are advantages that GPT has over MBR?
GPT has larger maximum storage space for partitions, and GPT stores boot data in multiple locations for redundancy.
MBR is to BIOS as __________ is to UEFI.
GPT. GPT is part of the UEFI standard
Which of the following is a hardware component that connects a host system to a storage device to facilitate input and output of data?
HBA
Which of the following hardware interfaces carries audio and video signals and is used to connect devices like monitors?
HDMI
You have a coworker who attempted to grow a file system on a Linux server. His problem is that the file system didn't extend despite entering the following command: sudo lvextend -L150G /dev/shared/ graphics —He remounted the file system onto /Graphics but the new space doesn't show up. What is the issue?
He forgot to issue the resizefs command to actually resize the file system. The lvextend command
You are in the testing phase of implementing some new services and SELinux keeps blocking external users from testing. How can you allow access without disabling SELinux or spending a lot of time setting up exceptions to allow all the ports required for testing?
Place SELinux in permissive mode—this leaves policies in place, but they are not enforced. As violations occur,
What is the significance of udev?
Prior to systemd and new kernels, the /dev/ directory only contained static device files—udev brings dynamic device
Why are /etc/passwd and /etc/shadow different files?
The /etc/passwd file stores user account details such as user names, default shell, home directory, and group names. The /etc/shadow file contains the hashed passwords that are only readable by the root user account, whereas /etc/passwd is readable by everyone. Having a separate file for each, with different permissions, strengthens security.
Your team has decided to use only one internal DNS server and one external. You must change the DNS server IP addresses on every Linux server. Which file can you edit to change the IP addresses?
The /etc/resolv.conf file contains the IP addresses of DNS servers.
Your Linux web server seems to have a memory problem that you can't pinpoint through checking web logs or system logs. Where can you look to find details about system memory usage?
The /proc/meminfo file contains
Explain the difference between /root and /
The /root directory is the root user's home directory and / is the root of the file system.
Which boot process component configures device drivers?
The BIOS/UEFI.
What is the purpose and function of a network adapter?
To provide an interface for connecting hosts to a network so that they can exchange data with one another.
True or false? Printers can use a wide variety of interfaces, and can even be accessed over a network.
True.
True or false? The Linux kernel is modular, enabling users to extend its functionality.
True.
Which of the following connection protocols may lshw not detect?
USB
You have created a script to check the existence of a file. If the file exists, you want to have the script echo the word "Success" and then exit with an exit code of 0. Otherwise, it should echo "Doesn't exist". Where in the script should you place the exit 0 code?
Within the if...then branch that tests the condition that the file exists, before the else branch.
The echo command is a very powerful one indeed. It can be used in scripts or interactively at the command-line to do several different things. How can you use the echo command to display your name on the screen?
echo "Bob Jones" —This command sends the output, Bob Jones, to the screen.
Choose which of the following code statements accurately produces the following output: The total is $50.
echo "The total is \$50."
Which of the following is the correct way to substitute array index 2 in Bash scripting?
echo $my_arr[2]
Which command can you use to create a new 400 GB logical volume, finance, from volume group vg_finance?
lvcreate --name finance --size 400G vg_finance
To access complete local documentation, which command can you enter at the command-line to access extensive usage information on the cp (copy) command?
man cp
There are two utilities that are good for paging through very long files with search capability. Both enable you to stop, proceed line-by-line, page-by- page, and to page up. Some administrators prefer one utility over the other because it has a few more options. What are these two utilities?
more and less
You have recently taken over support for a group of CentOS Linux servers formerly managed by a different system administrator. You have logged onto each one to check configurations and to update each system. When you attempted to update the systems, no updates were available. Which command can you run to find out which software repositories are configured?
yum repolist
During installation, why is it important to separate certain directories onto their own file systems?
Certain directories such as /home can fill up and crash the whole Linux server, so it is better to segregate those onto their own file systems, leaving the root file system (/) with available
What are the names and numbers of each layer of the OSI model? What is each layer's function?
Layer 7 (application) supports software and users; Layer 6 (presentation) formats data for use; Layer 5 (session) manages connections; Layer 4 (transport) manages reliable transmission of data; Layer 3 (network) manages logical addressing; Layer 2 (data link) manages physical addressing; Layer 1 (physical) enables physical connectivity.
What are the major functions performed by the kernel? (Choose two)
Process Management, and Memory Management
Your Windows users complain that there is no native SSH client in their older version of Windows. What can you recommend?
PuTTY is a commonly used SSH client for Windows.
True or false? If one of the CIA triad principles is compromised, the security of the organization is threatened.
True.
True or false? It is common for specialized Linux servers, such as firewalls, to contain more than one network adapter.
True.
True or false? The Uncomplicated Firewall (UFW) originated with Ubuntu but can be downloaded and installed on other distributions.
True.
Rose Stanley received an access denied message on a file. She used the ls -l command to discover what group had been granted access to the file. She believed she should be able to access the file. What suggestion would you make to address the issue?
Use the id command with Rose Stanley's account to ensure she is a member of the group specified by the file's permissions.
You're sure that you compiled and loaded the kernel module for your new Ethernet card, but the card doesn't work. How can you check to be sure the kernel module is loaded?
Use the lsmod command to list all currently loaded kernel modules.
Another system administrator has aliased the ls command to ls -la and you don't like to see that much output in a simple ls command. How can you temporarily remove the alias?
Use the unalias command: unalias ls
As an administrator, you attempt to set quotas on /opt/finance for the finance group, but you receive the error that the mount point /opt/ finance is not found or has no quota enabled. You verify that /opt/ finance exists. You're trying to enable quotas, so it makes no sense that the error is that the file system has no quotas enabled. What is the problem?
You didn't edit /etc/fstab to add usrquota,grpquota options to the file system you wish to impose quotas on. You also have to unmount/remount this file system after the change is made to /etc/fstab
You have a file that contains a very long list of activities (activities.txt) that were suggested by coworkers for things to do at the annual picnic. They are in no particular order, but you'd feel better if they were in alphabetical order, making them more readable. How can you rearrange the list into alphabetical order quickly?
sort activities.txt
Ruth has searched for a solution to her problem: A few of her training documents keep getting changed or removed by system administrators removing files that haven't been accessed in excess of 180 days. She has found that a file can be made immutable, but she cannot make her own files immutable and needs your assistance. How can you make the files /home/ ruth/training1_doc.txt and /home/ruth/ training2_doc.txt immutable?
sudo chattr +i /home/ruth/training*_doc.txt
The Graphics department requests that everyone in the company have access to company logo art to insert into emails, letterheads, and other documents. They do not want anyone outside of their group, however, to have any other access. A few days after requesting the change, other users still cannot access the files. You check permissions on the shared directory to find that the permissions are as follows: drwxrwx--- graphics GraphicsDept 4096 Dec 1 09:42 logos —What command can you issue to fix the problem?
sudo chmod o+r
You're a new system administrator and your manager comes to your cubicle to give you a pop quiz over a few concepts. The first one she asks you is to show her how you would set up a new partition on the second storage drive on a Linux system. Which command can you enter to perform this operation?
sudo fdisk /dev/sdb
Your manager asks you to find the number of times that connections from IP address 10.0.10.5 have connected to server1. These events are typically logged in the /var/log/auth.log file. Using piping, how can you get this count for him?
sudo grep 10.0.10.5 /var/log/auth.log | wc -l —This command searches for the string "10.0.10.5" in the authentication log and then pipes the output to the word count utility by the number of
You need to quickly create an empty file (log.txt) so that an application can copy data into it. Which command can you use to create the file?
touch log.txt
Which file forces system-wide customizations for all users on a system that a user cannot change?
/etc/profile
Which directory's contents are copied to the user's home directory upon account creation?
/etc/skel
You are scheduling new backup tasks on every new Linux system that your team configures and manages. Each requires its key directories to be backed up. Would the at command or a cron job be best for scheduling the backup script? Why?
A cron job is the correct choice because at is for running a task once, not for tasks that need repeating.
If you issue the following command: sudo umount /share1 and you receive the error that the resource is busy, how do you fix the problem and unmount the file system?
A program or user, possibly you, is using the /share1 directory. You must close the program or otherwise ensure
A junior administrator asks for your help with setting up a new Linux file system, /dev/sdb2. He retraces his steps with fdisk, creating the partition and saving the setup. But now, he can't figure out why he can't use the file system—how can you help him?
After inspecting his work in fdisk, you tell him that he must build the file system with the mkfs command. You assist him by entering the following command: sudo mkfs.ext4 /dev/sdb2
Why is multi-factor authentication effective in securing network and computing assets?
Because it doesn't simply rely on one factor of authentication, but adds another external knowledge
Develetech's security team requires that log files be archived for future reference and audits. Since you are responsible for several Linux servers, how can you make this process more efficient?
Answers may vary, but you can centralize the log files on a single Linux server.
What does the following command do? cat file.txt > /dev/null
Anything redirected to /dev/null has no output. It isn't saved to a file or displayed to the screen. It
You are giving a presentation to the IT and Security teams to convince them that you should adopt a new corporate standard for syslog services on your Linux systems. Your argument is that rsyslogd has several advantages or improvements over the standard syslogd service. What are some of those improvements?
Improvements include: TCP instead of UDP as the transport protocol; increasing the reliability of transmitted data; data encryption using SSL/TLS; outputting data to various database technologies like MySQL; buffering data on local systems when the remote receiver is not ready to accept it; filtering data based on content; and the rsyslogd log file format is backward compatible with the syslogd file format.
Where should administrators set system-wide variables on a Linux system rather than editing the /etc/profile file directly?
In scripts within the /etc/profile.d directory.
After a storage device controller failure, you restore the repaired system from backups. One of the directories you restore has hundreds of files with extensions such as .ksh, .bsh, and .csh. Unlike Windows, Linux file extensions have nothing to do with what type of file it is. Why might the owner of the files have added these extensions?
It is true that extensions do not determine the type of file, but it is an easy way to organize files and to know which shell they execute
What is the purpose of systemd during the boot process?
It mounts the file system based on the /etc/fstab file and begins the process of starting services.
What does the -h switch in the command df -h do for you?
It presents disk free (df) data in a human-readable format (megabytes and gigabytes) for mounted file systems.
You and your team have devised a backup plan that includes a full backup once a month and then incremental backups between full backups. What are the two primary advantages of this backup scheme?
It takes less time to perform incremental backups and it requires less space for the backups.
Executive management has decided to move toward a more agile infrastructure with mobile users and 100 percent hosted applications and infrastructure. This option enables employees to work from any location and relieves the company of hardware lifecycle and application support. Which option has the executive management decided to move to?
Public cloud offerings provide companies with off-premise infrastructure with some control of resources,
You have a few Debian-based Linux systems mixed in with your CentOS ones and you need to configure repositories for those. After adding a new repository to the /etc/apt/sources.list file, which command can you run to let APT know about the new repositories?
Run the apt update command.
It's 6:00 P.M. and you need to leave for the day. However, you also need to run an audit script that creates a report of all files that haven't been accessed in more than 180 days. If you log off, the script will stop running. How can you accomplish both—running the script and leaving work?
Run the script using the nohup command: sudo nohup fileaudit.sh
You SSH into a Linux system that only allows SSH access. The system is a web server and you've checked to see everything is working properly. However, no one can connect to the web server with a web browser. You suspect SELinux is in enforcing mode and blocking access. How can you check?
Run the sestatus command.
For Linux servers, which directories should typically be separated onto their own file systems?
Separate file systems should be created for
How can you list files in a hidden directory?
Similar to any other directory, either you cd into the hidden directory and issue the ls command or you explicitly name the hidden directory
You want to create a bootable DVD-ROM Linux distribution for some kiosk computers that customers will use to look up products while in your retail locations. Which new GRUB 2 improvement makes this an easier task compared to a few years ago?
Support for live booting makes
What is the main purpose of a function in programming and scripting?
To create a reusable chunk of code that performs a specific task.
Anyone can schedule cron jobs. As a regular user, you need to schedule a file transfer from your local workstation to the shared directory on one of the development servers. You need to create a new cron job. Which command can you use to create the cron job?
The crontab -e command is used to
Which of the search commands at your disposal would you use to locate a user's lost files, knowing that the user has access to dozens of directories and subdirectories as a member of several organizational groups?
The find command can locate files by owner or group, plus it displays the absolute path location.
You are creating a script that tests several conditions. Depending on the test outcome, you want one of three things to happen: send the results to a file, execute another script, or send all output to /dev/null. Which type of conditional statement can you use for this script?
The if...elif statement tests several conditions and can perform different actions based on which condition is met. You can also use the case statement to achieve the same result.
Why would an administrator use the ioping utility?
The ioping utility displays real-time I/O latency data
Why is it a security best practice to log onto a Linux system with a regular user account rather than with the root user account?
The primary reason is to prevent harmful mistakes from happening to the system through errant commands such as rm (remove). Users who can use the sudo command should do so on an individual command basis to perform necessary tasks with elevated privileges, while remaining in their user shells
You may configure swap space on a Linux system but not necessarily make it active until you feel like the system requires it. How can you enable a system's configured swap space?
The sudo swapon -a command activates all configured
You recently moved several Linux server systems from your local data center in the Eastern U.S. time zone to a disaster recovery data center in the Central U.S. time zone. You need to change time zones for those systems. What steps can you take to change the time zones?
Use sudo timedatectl list-timezones to find the correct format for the new time zone, which is America/Chicago. Use sudo timedatectl set-timezone America/Chicago
You log into a system that seems to have something incorrect in its configuration, but you are having trouble pinpointing why certain paths don't exist and why certain shell variables are set to non-standard values. How can you view all shell variables at once?
Use the set command with no arguments.
You have a CentOS system and you need to install an application that you know has a lot of dependencies. What can you do to satisfy those dependencies and install the application?
Use the yum install command to install the application and its dependencies automatically.
How does the Linux kernel manage devices?
User space applications send system calls, and the kernel reads the requests and passes them on to the drivers that manage device activities.
Jerry Robinson cannot use the cd command to navigate into a particular directory. He told the service desk that he used ls -l to see what group is associated with the file. He also confirmed that the group is listed as having read access to the directory. He then used the id command to confirm he is a member of that group. What suggestion would you make to address this issue?
Users also need the execute permission to change into a directory.
Rose Stanley opened a ticket indicating that she is denied the ability to delete a directory. She confirmed with the service desk that she has write permission to the directory. What suggestion would you make to address the issue?
Users also need the execute permission to remove a directory.
As a system administrator, what application of the tail command comes to mind first for checking on system status or an application's status?
Using tail on a log file to see the most recent entries should come to mind for checking the status of the system or an application.
Your company needs to transition from individuals running virtual machines locally on workstations to deploying virtual machines company-wide. Your team determines that it is more cost-effective for you to use VMware ESXi. VMware ESXi is which type of hypervisor? What does this mean?
VMware ESXi is a type 1 hypervisor. This means that the hypervisor runs on "bare metal" rather
You have created an internal repository for all your CentOS Linux servers but you are worried that it will be out of date in a few weeks. Downloading a new set of packages every few weeks is a daunting task. Is there any way to automate this process? If so, how?
Yes, the reposync utility updates the repository automatically.
The date command is very powerful, especially for use in scripts. You can add timestamps to log files and to script output. How can you display the day, date, and time using the date command?
date +"%A %F %X" —The
You decided to make all your systems more secure by adding a GRUB 2 boot loader password. After making the change to multiple systems, you feel confident that the new security measure will be effective in securing your systems. Which command can you use to generate a password for GRUB 2?
grub2-mkpasswd-pbkdf2
How would you use the printf command to display your name and address on different lines using a single command?
printf "Bob Jones\n 222 Pine Street" —The \n sends a newline character to output and places the address on a second line. You can get very sophisticated with newline
How can you remove the physical volume /dev/sde1?
pvremove /dev/sde1
Michael Anderson, a Develetech employee, calls you for help with software. He believes some files may have been deleted from his CentOS system, and now a piece of software he needs does not run. What command could you run to check that all the necessary components of the software are installed on the system?
rpm -V <package
The Marketing manager contacts you stating that the shared directory you set up for the Marketing group works, but not exactly like they'd planned. When one of the group members creates a file in the directory, the file takes on the user's user and group permissions. For example, when Linda creates a new file, the permissions are -rw-rw-r-- linda linda. The manager wants the files to all retain the mkt group permission, if possible, rather than having the users change the group themselves. What action can you take to fulfill this request?
sudo chmod -R g+s /opt/marketing —By setting the SGID on the directory, every file created by anyone in the mkt group will have the mkt group ownership.
Your manager asks you to copy all the files in the /opt directory to / backup for further inspection and analysis. Rather than copying every file and subdirectory manually, how can you copy /opt and all its contents to /backup with a single command?
sudo cp -R /opt /backup —This command copies the /opt directory recursively to /backup
You want to be sure that the Apache web server starts on boot. Which command can you use to ensure that it starts?
sudo systemctl enable httpd.service
Gina wants to share some marketing files with two other members of her team but doesn't want them to access those files in her home directory. She also wants the directory and its files to only be available to the Marketing group. What steps can you take as an administrator to accomplish this request?
1) You need to create a new group (mkt): sudo groupadd mkt 2) Add users to the group: sudo usermod -aG mkt gina linda mark 3) Create the shared directory: sudo mkdir /opt/marketing 4) Change group ownership to mkt: sudo chgrp mkt /opt/marketing 5) Change permissions so that the Marketing group has full control of the directory and its contents and remove everyone
A fellow administrator calls you and needs you to check the /etc/shadow file for a new user's entry, confirming that it indeed exists. How would you look at the contents of the /etc/shadow file without the possibility of changing the file?
1) su - 2) cat /etc/shadow —You first have to become the root user because the /etc/shadow file can only be read as root. To look at the file without the possibility of altering its contents,
How is Linux used in your organization? Are there any existing systems that could benefit from switching to Linux?
A: Answers will vary. Linux is a popular platform for hosting all kinds of servers, and if the students' organizations host or otherwise manage web servers, there's a high probability that they're running Linux. Most organizations use network appliances like routers to support their network, and many of these embedded devices run on Linux. If students' organizations implement any sort of mobile infrastructure policy, like bring your own device (BYOD), many of those devices are likely running Android, which is based on Linux. Switching an existing system to a new OS is not always an easy undertaking, but students may see the value in changing certain systems over to Linux if its free, simple, and modular nature improves performance and productivity.
Why might you choose to compile software from source code as opposed to using a pre-compiled package?
Answers may vary, but can include: The software may still be in development, so the package has not yet been created; there are no plans to create a package of the software at all; compiling from source code can support greater
What are two reasons why a network administrator might segment a network?
Answers may vary, but common reasons are to increase security by grouping hosts with similar security requirements together; and to increase
What is the difference between automation and orchestration? Why does this difference matter to Develetech?
Answers may vary, but automation manages one specific task, while orchestration manages an entire process or combination of individual tasks. It matters because orchestration benefits occur on a much larger scale than automation—for example, with the deployment
Rose Stanley, a graphic designer at Develetech, has asked for your help. She regularly transfers many very large image files. She wants an efficient way of doing this over the network. What network service do you recommend?
Answers may vary, but FTP is a good choice because it is designed for simple file transferring within a client/server architecture.
A change has been made to the configuration of a router by a member of the network team. Unfortunately, the change was not documented and the team member is unavailable. You have no access to the router itself. You would like to investigate what network traffic is moving on each side of the router to help determine what ports might have been closed. What tools might you use to gather network traffic on each side of the router?
Answers may vary, but could include tools like tcpdump and Wireshark.
Rose Stanley calls the help desk, registering a ticket that her Linux workstation does not have network connectivity. What process and tools might you suggest?
Answers may vary, but could include: a) Confirm the network cable is plugged in properly; b) Use the ip addr command to verify whether she has a valid IP address configuration. If the 169.254.x.x IP address is returned, her machine is not able to lease an IP address from the DHCP server; c) Attempt to ping one of the servers on the network that Rose might connect to. If the ping returns a "destination host unreachable" message, there is likely a configuration error on her Linux workstation; and d) Use traceroute to attempt to connect to a server. If the traceroute fails at a particular "hop" or router along the path,
One of the developers at Develetech has asked for your help. She needs a Linux test environment to verify her application functions as designed. She would like to manage it herself and be able to revert it back to its original configuration after each test. What solution can you suggest?
Answers may vary, but creating a virtual machine on a platform like KVM is a good choice because it is native to the Linux kernel.
Some users are concerned that their devices, whether USB, wireless, SCSI, etc., won't be compatible with Linux. What can you do to help ensure that these devices will work with Linux?
Answers may vary, but ensuring that Linux has the correct drivers installed for each device will help ensure that the devices work. Many device drivers come with Linux by default, so users may not even need
Can orchestration help Develetech with cloud-based web hosting? Why or why not?
Answers may vary, but for the most part, yes, orchestration works well with the cloud solutions of on-demand self-service
A junior Develetech server administrator believes that the bandwidth usage on his Linux server is being consumed by a particular network service. What tool could you suggest to him to gather information about exactly what protocols are using bandwidth on the NIC?
Answers may vary, but iftop is one of the most useful tools for this
After the administrator gathers the desired information, he discovers that there is no unexpected bandwidth usage by the services. He wonders if perhaps there is an issue on the network itself. He asks for a utility that would enable him to empirically test network bandwidth between two servers. What might you suggest?
Answers may vary, but iperf is one of the most useful tools for this job.
The Develetech IT staff recognizes the importance of solid documentation and wants to generate a representation of the entire network. The staff wants the information to include all routers and servers, as well as listening services and operating system information for each server. What tool might you suggest for this project?
Answers may vary, but nmap is one of the most useful tools for this job.
One of Develetech's server administrators is having difficulties with name resolution. She is responsible for both Linux and Windows servers. She wants to know if there is a single tool she can run from both of her servers to confirm they are receiving name resolution information from a specific DNS server.
Answers may vary, but nslookup is one of the most useful tools for this job.
When a user presses the Shift+2 on their keyboard, they expect the @ symbol to be entered, but instead, the # symbol is. What can you do to troubleshoot this issue?
Answers may vary, but the most useful approach to take is to examine the language and keyboard mapping settings on the computer. It's likely that the wrong keyboard format is set—to another language, region, or keyboard style— causing unexpected characters to be entered
An administrator has reported that a Linux server is sluggish, unresponsive, and frequently triggers a kernel panic with the error message "Machine Check Exception". What can you do to diagnose and fix this issue?
Answers may vary, but this particular error usually indicates faulty hardware. You can redirect the exact error code into the mcelog command to get more information about the error. Since the system is sluggish and unresponsive, you might see an error-correcting code (ECC) error, indicating that one of the memory modules has failed. You can then
You recently installed a new graphics card in one of your Linux systems that will be used by Develetech's video editor. The video editor notices sluggish performance and repeated crashes in their video editing software. You've deduced that the software isn't the source of the problem; the graphics card is. What step(s) should you take to try to solve this problem?
Answers may vary, but when it comes to graphics card issues, one of the most important troubleshooting steps is to ensure that you always download the latest drivers available from the manufacturer. These drivers often fix performance and stability issues, especially when the graphics card is put to use by video-intensive software.
Assuming you want to use a USB thumb drive to install Linux on these systems, what do you need to consider before doing so?
Answers may vary, but you need to ensure that the installation files are properly prepared on the drive, rather than just placing the files onto the drive like you would when storing data. You also need to ensure that the BIOS/UEFI environment supports
In what way are yum and apt more effective at managing software dependencies than rpm or dpkg?
Answers may vary, but yum and apt can automatically install dependency software, assuming that software is available in the repository.
Develetech will be providing LAMP (Linux, Apache, MySQL, PHP) web hosting packages for customers. How might orchestration benefit Develetech in this context?
Answers may vary. Orchestration can manage the entire deployment and configuration process of LAMP services. It can automate the deployment steps of Linux, the configuration of the Apache web service, database population of the MySQL database service, and the installation of the PHP programming language (or Perl or Python) components.
Which system would you set up for each purpose, and why?
Answers may vary. System A should probably go to the graphic designer, who will need lots of RAM, a top-of-the-line video card, and significant storage space for storing images and video files. System B should probably become the web server, as this configuration has the fastest networking capabilities, adequate RAM, fast storage technology, and a processor designed for servers. System C should probably become the test system, because its slower speed is more likely to reflect systems in production throughout the organization and therefore can more clearly illustrate how new software will perform
What steps might you take to implement a plan of action regarding the gathering of network traffic?
Answers will vary, but might include: a) Use a packet sniffer like Wireshark to observe what traffic is destined for the router on one segment; and b) Use a packet sniffer on the other segment to observe what traffic has been passed through the router, and what traffic has not. You can begin to infer what traffic is being blocked by the router with this information.
As part of the general roll-out at Develetech, what questions would you need to ask each user to be sure that the new system will meet their needs?
Answers will vary, but might include: questions that determine what applications users may need to run so you can confirm Linux support as well as adequate hardware requirements; and questions that elicit the network and security requirements for the web server.
One of Develetech's software developers has been programming on a Raspberry Pi device. He's been trying to connect the Pi's serial cable to a Linux system so that he can see the output of the program on the Linux console. However, the output doesn't appear. What can you do to troubleshoot this issue?
Answers will vary. You should perform standard steps like ensuring the correct drivers are installed, checking the physical cables for damage and to see if they're properly slotted into the serial port, etc. If this doesn't resolve the problem, you should make sure that the serial device is using the expected serial console, typically located at /dev/ttyS# where # is the number of the console (starting with 0). You may need to configure the Pi's settings so that it uses this console by default. Also, by default, only the root user is allowed to access serial ports. If necessary,
Since Linux is generally community (user) supported, name three sources of Linux documentation.
Any three of the following: Manual pages, built-in help commands, online documentation projects, Usenet newsgroups, Internet mailing lists, question and answer websites, forums
The application development team created a new web app and requested that you set up a web server-accessible directory and a service account for the application. After setting up everything for the team, they opened a ticket claiming that the application cannot write logs to the log directory. What is the issue, and how can you correct it?
As the root user, directories that you create are owned by root. You have to explicitly edit permissions to those directories. Change user and group ownership to the service account for any directory that the service needs to write to. The service account should have read and execute access to all other directories that it accesses. After creating a directory and subdirectories and copying files, it's generally a good practice to issue the following command: chown -R webapp:webapp /www/webapp —You can make permissions adjustments on individual directories and files as needed.
At a foundational level, many remote desktop protocols (e.g., NX, xrdp, SPICE, VNC) are not designed to be highly secure. How can you make them more secure?
By tunneling through SSH.
You're asked to design the network service implementation at a branch office location. There will be servers, printers, and workstations in the office. Which approach for assigning IP addresses to workstations would you take?
Dynamic IP address configurations are usually appropriate for client machines (workstations). They may also be used for network print devices.
A group of system administrators were discussing file permissions and decided that setting a particular root-owned text file to read-only for everyone is a best practice. What do the permissions for this file look like?
Either 664 or rw-rw-r-- is correct.
What protocol within the TCP/IP stack is responsible for logical addressing?
Internet Protocol (IP)
Your colleague has written a script with an array called names that holds the names of various users. In the script, a for loop iterates through each value in the array. The script is supposed to echo each name to the CLI, but instead, it only echoes the first name in the array multiple times. You confirm that the for loop has the proper syntax, so the problem must lie elsewhere. What do you think the problem is with the script?
It's likely that the echo statement within the for loop is referencing the $names array directly, whereas it should be referencing the iterator variable instead.
What is the purpose behind using a package manager to install software?
Package managers make it much easier to install software, control what software is installed, manage software versions, and uninstall
You want to provide secure connectivity to users in your company to a shared server for web and shell-based command-line access. Which protocols will you choose?
SSH for shell/command-line and HTTPS
What must happen before the boot loader can run?
The BIOS/UEFI must be initialized. The processor checks for the BIOS/UEFI firmware and executes it. BIOS/UEFI checks for bootable media and locates a valid device to boot the system. BIOS/UEFI then
Several of your users want to install and use Linux at home but are confused by firewall rules and managing a firewall for themselves. What tool can you recommend to help them configure their firewalls?
The Uncomplicated Firewall (UFW) is a tool primarily useful for home users who don't have the experience with the intricacies of firewall configuration.
What is the advantage of using an off-site backup and how can you transfer files from the main site to an off-site facility?
The advantage is that, in case of a disaster, the data at the off-site facility is probably safe. You can transfer
You want to set up SSH keys to better secure your SSH communications between your Linux desktop system and your Linux servers. Which command can you use to generate the public/private key pair?
The ssh-keygen command generates the public/private key
What is the importance of the initrd phase of the boot process?
The initrd enables the system to be started in two phases. In the first phase, the system is booted with the minimal set of modules required to load the main, or permanent, root file system. In the second phase, when the main root file system is mounted, the previously mounted initrd file system is removed and the user space boot process continues.
How does the Linux kernel handle memory management for applications?
The kernel maps or allocates the available memory to applications or programs on request and frees the memory automatically when the execution of the programs is complete. This ensures that memory can be allocated to other
Some files were deleted from a shared directory after regular business hours last night and the other users want to know who was responsible for the deletions. To find out who was on the system during the suspected times, you use the last command. From which log file does the last command read its data?
The last command retrieves information from the /var/log/wtmp file.
You suspect that some users have not logged into the file server to update their passwords since the new file server went into production. Which command lists all users and the last time they logged in?
The lastlog command displays the list of users and the last time they logged into the system.
For a quick glance at CPU performance, what does the uptime command tell you about the system?
The uptime command displays the CPU's load average for the last 1, 5, and 15 minutes.
What are some advantages of using the find command over using the locate command?
The locate command requires that a database be updated in order to perform accurate searches, whereas find does not. Also, locate cannot filter its search by specific directories, whereas find can. However, locate may be able to perform searches more quickly
You need to set up a log rotation schedule that's relatively maintenance- free. In other words, you don't want to have to purge logs from 30 servers on a regular basis—you want it to happen automatically. Which utility provides this service on a schedule that you determine?
The logrotate utility is used to perform automatic rotation of logs.
The developers at your company have created custom kernel modules to optimize in-house application performance. They supply you with all the necessary files to load the new modules, including dependent modules. When you load the first primary module using modprobe you receive multiple errors and the modules don't load because of broken dependencies. Which file or files can you examine to find the issues?
The modules.dep file is the likely problem. This file identifies how modules and their dependencies are linked.
Answers will vary, but might include: questions that determine what applications users may need to run so you can confirm Linux support as well as adequate hardware requirements; and questions that elicit the network and security requirements for the web server.
The most common method of installing Linux is booting and installing from removable media, such as DVDs or USB thumb drives.
If you cd to the root directory of the file system, name three directories that you'll see there.
The root of the file system is / and some possibilities are: /etc, /home, / opt, /mnt, /media, /boot, /dev, /proc, /tmp, /var, /lib, /bin, / sbin, /sys, /root, and /usr
Andrew Riley, a Develetech Marketing department employee, has been given privileges for installing software on his Ubuntu laptop. He has downloaded a package and is using the rpm -ivh <package name.rpm> command to install the software. He says the system error indicates that the rpm command is not found. What is the issue?
The rpm command is not available by default on Ubuntu, and is instead found on Red Hat-derived distros.
A senior-level administrator performed an audit on your backups and commended you for using SFTP to encrypt data as it traverses the network and the Internet. However, he introduces you to a new command, rsync, that has a particularly interesting advantage over SFTP. What is that advantage?
The rsync command can copy files over SSH, but it also synchronizes (copies differences between) files, rather than copying the entire contents of a directory. Therefore, it
You made a change to the /etc/httpd/conf/httpd.conf file and saved it, but the change you made hasn't taken effect. What is the problem and how do you fix it?
The service needs to be restarted so the configuration file can be re-read and the changes applied: sudo systemctl restart httpd.service
You are editing an old backup script and find the line source directories.sh in the script. Displaying the contents of the script reveals a list of exported directory names as variables. What is the purpose of using the source command in the backup script?
The source command executes the other script, directories.sh, in the current shell. This provides all the exported variables to the backup script.
The vmstat command is useful for displaying an overall performance snapshot, but running it once only displays information since the last reboot. How can you see a more comprehensive view of system performance using the vmstat command?
The standard command to see system performance statistics using the vmstat command is vmstat 5 5 —This provides you with a comparison view from last reboot and four updated snapshots.
Your manager comes to you to discuss performing some no-cost security hardening on your Linux systems. Specifically, she asks you to protect the kernel from attacks. Which command and associated configuration file can you investigate to assist you in this task?
The sysctl command and its configuration file, sysctl.conf, are used to tune and to set security parameters for a
Linux administrators don't enjoy seeing a kernel panic during the boot process because it means that the system won't recover on its own and something serious has happened. What are some possible causes of a kernel panic that occur during the boot process?
The system has a corrupted kernel, the system program didn't execute, the kernel can't find or mount the root
Being security conscious, you always check out any software package being installed to your CentOS systems. Which command can you run to check supporting software packages prior to installing a new software application?
The yum deplist command displays dependencies so that you can see what's going to be installed with an application
There is much debate among your team concerning whether to deploy virtual machines with thick-provisioned storage or thin-provisioned storage. What the debate boils down to is performance. Which provisioning type has better performance?
Thick provisioning has better performance because all space is allocated at configuration time and the storage capacity is fixed rather than dynamic. Fixed capacity has better performance because
The find command is one of the most powerful in a system administrator's toolbox. What does the following find command do? find / -name "carbon*" -print
This find command searches from the root (/) directory and all subdirectories for any files beginning with the word "carbon" and their locations.
What is the term used to describe the situation where a process fails to free up allocated memory when it is no longer needed?
This is referred to as a memory leak.
What is the purpose of a logical operator in programming and scripting?
To connect values so that they can be evaluated together.
You have used Red Hat Enterprise Linux and some of its derivative distributions, but you want to try a Debian-based distribution because of the APT package manager. Aside from Debian itself, what are some common Debian-based distributions you can choose from?
Ubuntu, Linux Mint, Kali Linux, SteamOS, and openSUSE are all common Debian-based distributions available to you that use
Your development team at Develetech needs to modify some MySQL database software to optimize it for a database application. You have installed MySQL using YUM. What do you need to do to accommodate the modification need?
Uninstall MySQL using YUM. Have the developers acquire the MySQL source code, modify it, and then you can compile and install the software manually.
You created a shared directory for the Marketing planners, Linda and Mark, named /opt/MPlans. Their group, mplan, has exclusive access to this directory. No other user can access the directory or its contents. Linda decides that Gina needs read-only access to a single file, history.txt, inside the /opt/MPlans directory. Is this kind of restrictive access possible? If so, how can you grant it to Gina?
Yes, it is possible through ACLs. First, grant Gina read and execute access to the directory: setfacl -m u:gina:rx /opt/MPlans and then, set read access to the history.txt file inside the MPlans directory: setfacl - m u:gina:r /opt/MPlans/history.txt —You can check your
A user, John, opened a ticket complaining that he has files in his home directory that he cannot remove, although they are his files and he is the user and group owner. He requests that you remove the files /home/ john/billing1.txt, billing2.txt, and summary.txt. However, when you attempt to remove the files, you receive an error that you cannot remove the files as the root user. What is a possible resolution for John?
You can issue the lsattr command to see if immutable flag has been set on those files. If it has, you can resolve the problem by removing the immutable flag and then removing the files: 1) sudo chattr -i /home/john/
You need to provide shared Linux resources to Windows users. Which service can you set up on your Linux system to accomplish this?
You can set up Samba to create
You and the security team decide that, to enhance the security at Develetech, you need to use something more secure than passwords for your SSH sessions. What other authentication method can you employ to increase security?
You can set up public-key
Gina, a member of the Marketing group, has decided that she wants her files protected so that only she can delete them, although other Marketing group members need to be able to work on and edit the files. What can she do to fix the problem of others deleting her files?
You can show Gina the following command to set the sticky bit on her files: chmod +t filename.txt —This command
In your script, you want to echo the following message back to the user: "Hello, user. Please select an option to begin." You want "user" to be replaced by the name of the currently logged-in user. How can you do this no matter who is logged in?
You can use command substitution: echo "Hello, $(whoami). Please select an option to begin."
For text file editing in Linux, you have options other than Vim. Name one graphical editor and one other command-line interface (CLI) editor that you might use instead of Vim.
You can use gedit for the graphical editor and GNU nano for the CLI editor.
You want to create a shell script using Vim. You enter Vim but can't type any letters. What do you need to do before you can begin typing?
You have to press i for insert mode and then begin typing
What are usually the first two pieces of information you are prompted to provide during a Linux installation?
You have to select a keyboard layout and system language.
A user (Bob Smith—username: bsmith) calls you to request that you restore a group of files he accidentally deleted from his home directory. You copy the files for him but he later complains that he can no longer edit the files. What do you need to do so that he can edit his files?
You need to change ownership of the files to him. Change user and group ownership recursively so that Bob owns all files and directories. For example: sudo chown -R bsmith:bsmith *
Why should you have to unmount a file system prior to performing an fsck on it?
You should unmount the file system to prevent damage such as file corruption.
How can you edit the GRUB 2 boot loader during the boot process?
You start or reboot the system, then, on the GRUB 2 boot menu press Esc. Next, highlight one of the entries, press e, edit the configuration, then press Esc. Finally, press Enter to boot using your option.
A user changed the permissions of a script (myscript.sh) in a shared directory. The user is curious why everyone can execute the script if the user owns the script and everyone else only has read access. To make the script executable, what command did the user mistakenly issue?
chmod +x myscript.sh —The permissions changed to rwxrwxr-x or 775, which gives everyone execute permission. To limit execute permission to the user and group only, the command should have
Your team lead is tired of receiving help desk tickets to restore deleted files from a directory that contains hundreds of files and subdirectories. She decides to have you fix the problem by making all of the files read-only. How do you change all the files to read-only without having to traverse each directory?
chmod -R 644 * —This command changes all files in the current directory
A user cannot execute a script (collect.sh) she created and has sent you the contents of the script via email to inspect. After looking at the script, you determine the script is correctly written but permissions are the problem. What command can you issue to adjust the file's permissions as necessary?
chmod u+x collect.sh
Which of the following is the correct way to substitute a variable in Bash scripting?
echo $my_name
Some of your users have complained about one of the development servers being slow. With what command can you check the memory statistics that give you the best quick snapshot of memory performance?
free -h -t gives you a complete look at memory performance in human- readable format. This also includes used swap space, which is important for determining if a system has serious
What does the lsusb command display?
lsusb displays all USB buses and a list of USB-attached devices and the buses they're connected to. The list will likely be different for every system.
Your company has deployed physical systems in its data centers rather than virtual ones. Physical systems often experience some time drift if not calibrated with an external source, such as an NTP server. You should set the hardware clock to UTC and also correct any time differences by telling the hardware clock to compensate for drift. How can you set the hardware clock and adjust for drift?
sudo hwclock -u sets the clock to UTC and sudo hwclock -- adjust compensates for drift.
After installing the Apache web server, httpd, you want to check its status. How can you check the status of the httpd service?
sudo systemctl status httpd.service
How can you unmount the /finance file system?
sudo umount /finance
You tried using locate to find README files on your new Linux system but quickly realized that it wasn't installed at build time. After installation, you tried using locate to find README files, but again the command has failed to find anything. You discover that for locate to work, you must build the mlocate database. Which command can you run to build the mlocate database?
sudo updatedb
With which command can you change the default user shell to the KornShell for user bsmith?
sudo usermod -s /bin/ksh bsmith
You have taken a position as a system administrator at a new company and have done some discovery work on the environment. You've noticed that multiple software packages are more than one year out of date on several CentOS systems. Using YUM, which command can you issue to update all software packages on each system without acknowledging or confirming the update?
sudo yum -y
You want to install the xterm package onto your Linux workstation and don't want to wait for xterm and all its dependencies to be found before you acknowledge the installation. Using YUM, how can you install xterm and its dependencies without having to interact with the installation?
sudo yum -y install xterm
You need to install several packages that the developers have downloaded and placed into a shared directory (/scratch). These are all RPM packages. How can you install the rdesktop-0.9.rpm package, for example?
sudo yum localinstall /scratch/rdesktop-0.9.rpm
You need to remove the Apache web service software package (httpd) so that you can install via source code. Using YUM, what command can you issue to uninstall Apache?
sudo yum remove httpd
If you know the name of a command and want to know what its function is, which command would you use to find out?
whatis
You and other junior Linux administrators have noticed that some basic commands don't have man pages associated with them. You would like to know which ones do. One of the other administrators told you about a command that would also list the man pages for a command search. To which command was he referring?
whereis
