EX200 Essential Tools Practice Test 3 — 15 Questions

Question 1

A system administrator needs to find all files modified in the last 24 hours under /var/log. Which command accomplishes this?

Accepted Answer

find /var/log -mtime -1. `find /var/log -mtime -1` searches for files under `/var/log` whose modification time (`mtime`) is less than 1 day ago (i.e., modified within the last 24 hours). The `-mtime` flag checks the last modification time of file content, which is the standard criterion for 'modified' files.

Answer

find /var/log -ctime -1

Answer

find /var/log -atime -1

Answer

find /var/log -mmin 1440

Question 2

A user reports that they cannot use the 'systemctl' command to manage services. The user is part of the 'wheel' group. Which configuration change is required to allow this?

Accepted Answer

Ensure /etc/polkit-1/rules.d/10-admin.rules includes an admin rule for the wheel group. The 'systemctl' command requires PolicyKit authorization for non-root users to manage systemd services. The correct configuration is to add a PolicyKit rule in /etc/polkit-1/rules.d/10-admin.rules that grants the 'wheel' group administrative privileges, allowing them to invoke systemctl without a password or with appropriate authentication.

Answer

Set the 'permissive' mode for systemd via systemd.conf

Answer

Add the user to the 'systemd-journal' group

Answer

Add the user to /etc/sudoers with 'ALL ALL=(ALL) ALL'

Question 3

During boot, a server fails to mount an NFS filesystem listed in /etc/fstab. Which troubleshooting step should be taken first to isolate the issue?

Accepted Answer

Check the status of remote-fs.target with 'systemctl status remote-fs.target'. When an NFS filesystem fails to mount during boot, the first step is to check whether the remote-fs.target unit is active. This target is responsible for triggering the mounting of all remote filesystems (including NFS) after the network is available. If remote-fs.target is not active or has failed, the NFS mount will not be attempted, and troubleshooting should start here before investigating the NFS share itself.

Answer

Check the status of nfs-client.target with 'systemctl status nfs-client.target'

Answer

Try to manually mount the NFS share with 'mount /mnt/nfs'

Answer

View kernel messages with 'dmesg | grep -i nfs'

Question 4

A script needs to be run at system boot for a specific user. Which method ensures the script runs with that user's environment?

Accepted Answer

Create a systemd user unit in ~/.config/systemd/user/. Systemd user units, placed in ~/.config/systemd/user/, are executed in the user's own session context, inheriting the user's environment variables, PATH, and D-Bus session. This ensures the script runs with the specific user's environment at boot, as systemd starts the user manager (systemd --user) early in the boot process for each enabled user.

Answer

Place the script in /etc/rc.d/rc.local

Answer

Add an entry to ~/.xprofile

Answer

Add the script to the user's crontab with @reboot

Question 5

Which command displays the current system time, timezone, and whether NTP synchronization is active?

Accepted Answer

timedatectl. The `timedatectl` command (option C) is the correct tool in Red Hat Enterprise Linux (RHEL) for querying and configuring system time, timezone, and NTP synchronization status. It displays the current local time, timezone, and whether NTP is active or enabled in a single, clear output, making it the standard utility for these tasks in systemd-based systems.

Answer

ntpq -p

Answer

date

Answer

cal

Question 6

An administrator needs to monitor network traffic on a specific interface in real time. Which tool is most appropriate for this task?

Accepted Answer

tcpdump -i eth0. tcpdump -i eth0 captures and displays packet headers in real time on the specified interface (eth0). It uses libpcap to intercept raw network frames at the data link layer, making it the standard tool for live traffic monitoring and analysis.

Answer

ip -s link

Answer

ss -tulpn

Answer

nload eth0

Question 7

A developer needs to compile software from source and install it under /opt/custom. To avoid affecting the system package manager, which approach should be used?

Accepted Answer

Compile with './configure --prefix=/opt/custom' and then 'make install'. Using `./configure --prefix=/opt/custom` sets the installation root to `/opt/custom`, which keeps the compiled software completely separate from the system-managed directories (e.g., `/usr`, `/usr/local`). Running `make install` then installs all files under this custom prefix, ensuring the system package manager (RPM/YUM/DNF) is not affected by the manual installation.

Answer

Compile and install with default paths, then use 'make uninstall' to remove

Answer

Compile with './configure --prefix=/opt/custom' and use 'checkinstall' to create an RPM

Answer

Compile with './configure --prefix=/usr' and then install

Question 8

Which TWO commands can be used to display the contents of a compressed log file without decompressing it first?

Accepted Answer

bzless /var/log/messages.bz2. `bzless` is a utility specifically designed to view bzip2-compressed files without decompressing them first. It decompresses the file on the fly and pipes the output to a pager, allowing you to scroll through the content. Similarly, option B is correct because `zcat` reads a gzip-compressed file and writes the decompressed data to standard output, effectively displaying the contents without permanently decompressing the file.

Answer

grep 'error' /var/log/messages.gz

Answer

vim /var/log/messages.gz

Answer

less /var/log/messages.gz

Question 9

Which TWO methods can be used to permanently set the system's hostname to 'server01.example.com'?

Accepted Answer

hostnamectl set-hostname server01.example.com. `hostnamectl set-hostname server01.example.com` is the systemd-based command that permanently sets the hostname by writing to `/etc/hostname` and applying the change immediately via the `hostnamed` service. This is the recommended method on RHEL 8/9 systems, as it updates both the transient and static hostnames, ensuring persistence across reboots.

Answer

echo '127.0.1.1 server01.example.com' >> /etc/hosts

Answer

hostname server01.example.com

Answer

echo 'HOSTNAME=server01.example.com' >> /etc/sysconfig/network

Question 10

Which THREE file descriptors are always available for every Unix process?

Accepted Answer

2: stderr. File descriptor 2 (stderr) is one of the three standard file descriptors that every Unix process inherits from its parent process. These descriptors are opened automatically by the kernel when a process starts, providing default channels for input (stdin, fd 0), output (stdout, fd 1), and error output (stderr, fd 2).

Answer

4: socket

Answer

3: log file

Question 11

Which command displays the current working directory?

Accepted Answer

pwd. The `pwd` command stands for 'print working directory' and is the standard Linux/Unix command to display the absolute path of the current directory. It is part of the GNU Core Utilities and is the correct tool for this task in the Red Hat Enterprise Linux environment tested in EX200.

Answer

ls

Answer

dir

Answer

cd

Question 12

A user needs to find all files with the '.conf' extension under /etc. Which command should be used?

Accepted Answer

find /etc -name "*.conf". The `find` command is designed to search for files and directories based on criteria such as name, type, or size. Using `find /etc -name "*.conf"` recursively searches the entire `/etc` directory tree for files ending in `.conf`, which is the standard and most reliable method for this task.

Answer

grep -r "*.conf" /etc

Answer

locate /etc/*.conf

Answer

ls /etc/*.conf

Question 13

An administrator wants to gracefully terminate a process with PID 12345. Which command should be used?

Accepted Answer

kill -TERM 12345. `kill -TERM` (or `kill -15`) sends the SIGTERM signal, which requests a process to terminate gracefully. This allows the process to perform cleanup tasks (e.g., closing files, releasing resources) before exiting, making it the standard way to stop a process politely.

Answer

kill -STOP 12345

Answer

kill -9 12345

Answer

kill -KILL 12345

Question 14

A system administrator needs to replace all occurrences of 'enabled' with 'disabled' in /etc/ssh/sshd_config, but only on lines that do not start with '#'. Which sed command accomplishes this?

Accepted Answer

sed '/^#/!s/enabled/disabled/g' /etc/ssh/sshd_config. It uses an address range `/^#/!` to negate lines starting with `#` (comments), then applies the substitution `s/enabled/disabled/g` only to non-comment lines. The `!` operator inverts the match, so the command acts on lines that do NOT match the pattern, which is exactly what the requirement specifies.

Answer

sed 's/enabled/disabled/g' /etc/ssh/sshd_config

Answer

sed -n '/^#/!s/enabled/disabled/gp' /etc/ssh/sshd_config

Answer

sed '/^#/s/enabled/disabled/g' /etc/ssh/sshd_config

Question 15

A user wants to display the contents of a file in reverse line order. Which command should be used?

Accepted Answer

tac file. The `tac` command is the standard Linux utility for displaying a file in reverse line order. It reads the file from the last line to the first, effectively reversing the line sequence. This is the correct tool for the task described.

Answer

tail -r file

Answer

sort -r file

Answer

rev file