XK0-006 System Management Practice Test 10 — 15 Questions

Question 1

Which command displays the amount of free and used disk space on all mounted file systems in a human-readable format?

Accepted Answer

df -h. The df command reports file system disk space usage, and the -h flag renders sizes in human-readable units (K, M, G). Running df -h shows all mounted file systems with total, used, available space, and mount point. This is the standard Linux utility for checking free and used disk space.

Answer

du -h /

Answer

lsblk -h

Answer

mount -h

Question 2

An administrator wants to change the default systemd target to multi-user.target so the system boots to a text console. Which command should be used?

Accepted Answer

systemctl set-default multi-user.target. systemctl set-default multi-user.target sets the default target. systemctl isolate changes the current target but not the default. enable and mask are for services, not targets.

Answer

systemctl isolate multi-user.target

Answer

systemctl enable multi-user.target

Answer

systemctl mask multi-user.target

Question 3

A technician needs to search a log file for lines containing either 'ERROR' or 'FATAL' and display the line numbers. Which command accomplishes this?

Accepted Answer

grep -n -E 'ERROR|FATAL' logfile. grep -n -E 'ERROR|FATAL' logfile uses extended regex with alternation and -n for line numbers. -i ignores case, but the stem does not mention case-insensitive; -v inverts match; -r is recursive.

Answer

grep -v -E 'ERROR|FATAL' logfile

Answer

grep -r -n 'ERROR|FATAL' logfile

Answer

grep -i 'ERROR|FATAL' logfile

Question 4

A system administrator runs 'umask 027' in a Bash shell. What will be the default permissions for a new directory created in that shell? (Assume no other umask changes.)

Accepted Answer

rwxr-x--- (750). The umask value 027 subtracts permissions from the base 777 for directories. 777 minus 027 equals 750, which translates to rwxr-x---. The owner gets full permissions (rwx), the group gets read and execute (r-x), and others get no permissions (---).

Answer

rwxrwxr-x (775)

Answer

rwxrwxrwx (777)

Answer

rw-rw-r-- (664)

Question 5

A process is consuming excessive CPU and needs to be terminated immediately. The PID is 1234. Which command will terminate the process with the most forceful signal?

Accepted Answer

kill -9 1234. kill -9 (SIGKILL) forcibly terminates the process. SIGTERM (15) is graceful; SIGHUP (1) reloads config; SIGSTOP (19) suspends.

Answer

kill -15 1234

Answer

kill -1 1234

Answer

kill -19 1234

Question 6

Which directory in the Filesystem Hierarchy Standard (FHS) contains essential user commands available to all users, such as 'ls' and 'cp'?

Accepted Answer

/bin. The /bin directory in the FHS contains essential user commands that must be available in single-user mode and for all users, such as ls, cp, mv, and cat. These binaries are required for basic system operation and are on the root filesystem so they are available even when other filesystems are not mounted. This matches the question's description precisely.

Answer

/sbin

Answer

/opt

Answer

/usr/bin

Question 7

A Linux administrator needs to view real-time information about running processes, including CPU and memory usage. Which TWO commands can be used for this purpose? (Choose two.)

Accepted Answer

top. Option B (top) is correct because top provides a continuously refreshing, real-time view of running processes along with per-process CPU and memory usage, load averages, and system summary statistics. Option D (htop) is correct because htop is an interactive process viewer that also displays real-time CPU and memory usage per process, with additional features like colorized output, scrolling, and process management. Option A (ps aux) is not correct here because ps produces a static snapshot of processes at the moment it is executed rather than a live, updating view. Option C (systemctl list-units) is incorrect because it lists systemd units and their states, not per-process CPU or memory usage. Option E (kill -l) is incorrect because it only lists available signal names/numbers and provides no process resource information.

Answer

ps aux

Answer

systemctl list-units

Answer

kill -l

Question 8

An administrator needs to grant read and write access to the 'developers' group on a directory while preserving existing permissions for the owner and others. Which TWO commands can be used to modify ACLs? (Choose two.)

Accepted Answer

setfacl -m g:developers:rw /dir. setfacl -m g:developers:rw /dir is the correct command to grant read-write access to the developers group. Option C uses u:developers, which sets an ACL for a user named 'developers', not the developers group, so it does not satisfy the requirement. chmod changes standard permissions, getfacl only displays ACLs, and setfacl -x removes ACL entries. Therefore, only option E is correct.

Answer

chmod g+rw /dir

Answer

getfacl /dir

Answer

setfacl -m u:developers:rw /dir

Answer

setfacl -x g:developers /dir

Question 9

A Linux administrator needs to change the permissions of a file to be readable and writable by the owner, readable by the group, and no access for others. Which command accomplishes this?

Accepted Answer

chmod 640 file. chmod 640 sets owner read+write (6), group read (4), and others no access (0), which matches the requirement exactly. The octal notation maps 4=read, 2=write, 1=execute, so 6=rw, 4=r, 0=none. This is the standard permission set for files that should be private to the owner but readable by a trusted group.

Answer

chmod 600 file

Answer

chmod 664 file

Answer

chmod 644 file

Question 10

A system administrator wants to find all files in /var/log that have been modified in the last 7 days and are larger than 100MB. Which command should be used?

Accepted Answer

find /var/log -mtime -7 -size +100M. The find command with -mtime -7 matches files modified within the last 7 days (the minus sign means 'less than 7 days ago'), and -size +100M matches files larger than 100MB (the plus sign means 'greater than'). This combination precisely satisfies both conditions.

Answer

find /var/log -mtime +7 -size +100M

Answer

find /var/log -atime -7 -size +100M

Answer

find /var/log -mtime -7 -size -100M

Question 11

A developer wants to grant a user named 'john' read and write permissions to a file, but the file currently has an ACL that gives 'jane' full control. The administrator wants to add an ACL entry for 'john' without modifying existing entries. Which command accomplishes this?

Accepted Answer

setfacl -m u:john:rw file. The `setfacl -m` command modifies the ACL by adding or updating an entry for the specified user, leaving all other existing ACL entries intact. This directly satisfies the requirement to grant 'john' read and write permissions without altering 'jane's full control entry. The `-m` flag is specifically designed for modifying ACLs in this additive manner.

Answer

setfacl -x u:john:rw file

Answer

setfacl -b u:john:rw file

Answer

chmod u+rw file; setfacl -m u:john:rw file

Question 12

Which of the following commands will display the last 10 lines of a log file and also output new lines as they are appended?

Accepted Answer

tail -f logfile. The `tail -f logfile` command displays the last 10 lines of the file by default and then continues to monitor the file for new lines, outputting them as they are appended. The `-f` (follow) option keeps the file open and polls for changes, making it the standard tool for real-time log monitoring.

Answer

head -f logfile

Answer

less +F logfile

Answer

cat logfile

Question 13

A user wants to run a command that will continue running even after the user logs out. Which command should be used?

Accepted Answer

nohup command &. nohup makes the command immune to hangups and runs in the background.

Answer

disown command

Answer

command &

Answer

bg command

Question 14

Which directory in the FHS contains essential user command binaries that are needed in single-user mode?

Accepted Answer

/bin. The /bin directory, as defined by the Filesystem Hierarchy Standard (FHS), contains essential user command binaries (e.g., ls, cp, mv) that are required for booting, repairing, and operating the system in single-user mode. Single-user mode mounts only the root filesystem, so /bin must be on the root partition to provide these critical utilities without relying on other filesystems like /usr.

Answer

/usr/bin

Answer

/sbin

Answer

/opt/bin

Question 15

An administrator needs to permanently mount an ext4 filesystem on /dev/sdb1 to the /data directory. Which file must be edited to ensure the mount persists across reboots?

Accepted Answer

/etc/fstab. The /etc/fstab file is the system's static filesystem table, read by systemd or the init scripts during boot to mount filesystems automatically. To make a mount persistent, you add an entry specifying the device (/dev/sdb1), mount point (/data), filesystem type (ext4), and options (e.g., defaults). This ensures the kernel mounts the filesystem on every reboot without manual intervention.

Answer

/etc/sysconfig/network

Answer

/etc/default/grub

Answer

/etc/mtab