EX200 Essential Tools Practice Test 2 — 15 Questions

Question 1

An administrator wants to ensure that when a user presses Ctrl+C during a long-running script, the script cleans up temporary files before exiting. Which approach should the script use?

Accepted Answer

Use 'trap' to catch SIGINT and run cleanup.. The `trap` command in Bash allows a script to catch signals like SIGINT (sent when Ctrl+C is pressed) and execute a custom function or command before exiting. By setting `trap cleanup SIGINT`, the script can remove temporary files or perform other cleanup actions automatically, ensuring a graceful termination.

Answer

Use 'set -o ignoreeof' to ignore Ctrl+C.

Answer

Run the script in the background with '&'.

Answer

Use 'set -e' to exit on any error.

Question 2

A user needs to view the last 15 lines of a log file that is constantly being updated. Which command should they use?

Accepted Answer

tail -n 15 /var/log/messages. The `tail -n 15 /var/log/messages` command displays the last 15 lines of the specified log file without following it. This meets the requirement to view the last 15 lines of a file that is constantly being updated, as it provides a static snapshot of the most recent entries.

Answer

tail -f /var/log/messages

Answer

cat /var/log/messages

Answer

head -15 /var/log/messages

Question 3

An administrator needs to compress a directory 'data' into an archive named backup.tar.gz using gzip compression. Which command should they use?

Accepted Answer

tar -czf backup.tar.gz data. The `tar -czf` command creates a compressed archive: `-c` creates a new archive, `-z` filters the archive through gzip compression, `-f` specifies the archive filename `backup.tar.gz`, and `data` is the directory to archive. This produces a tarball compressed with gzip, matching the requirement exactly.

Answer

gzip -r data > backup.tar.gz

Answer

tar -cjf backup.tar.gz data

Answer

tar -xzf backup.tar.gz data

Question 4

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 5

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 6

An administrator wants to edit a configuration file and ensure only the intended changes are saved. Which practice is recommended?

Accepted Answer

Use 'git' to track changes and commit after editing. Using 'git' to track changes and commit after editing provides a version control system that allows you to review, stage, and commit only the intended modifications. This ensures that unintended changes are not saved, as you can use 'git diff' to verify changes before committing and 'git checkout' to revert unwanted edits. Git is a standard tool for system administration and provides a robust method for configuration file management.

Answer

Copy the file to a temporary location, edit, and then overwrite

Answer

Use 'ls -l' to check the file size before and after editing

Answer

Edit the file in place with a backup using 'sed -i.bak'

Question 7

A server has a disk with LVM logical volumes. The administrator needs to extend a logical volume to use all remaining free space in the volume group. Which command sequence is correct?

Accepted Answer

lvextend -l +100%FREE /dev/vg/lv && xfs_growfs /dev/vg/lv. `lvextend -l +100%FREE` extends the logical volume to use all remaining free extents in the volume group, and `xfs_growfs` is the correct command to grow an XFS filesystem online. This sequence ensures the logical volume and filesystem both utilize all available space without unmounting.

Answer

lvextend -L +100%FREE /dev/vg/lv && resize2fs /dev/vg/lv

Answer

lvextend -l +50%FREE /dev/vg/lv && xfs_growfs /dev/vg/lv

Answer

lvresize -L +100%VG /dev/vg/lv && resize2fs /dev/vg/lv

Question 8

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 9

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 10

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 11

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 12

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 13

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 14

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 15

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