CompTIA Linux+ XK0-004 actual Exam with complete accurate questions and answers with rationales ( 2025-2026 latest release )

While using the BASH, which of the following commands will switch the default display in such a way that new applications will appear on the remote machine 192.168.1.50?

A. display 192.168.1.50

B. export DISPLAY=192.168.1.50

C. export TARGET=192.168.1.50

D. switch 192.168.1.50

B. export DISPLAY=192.168.1.50

Which of the following commands will display a user's current environment variables? (Select TWO)

A. env

B. info env

C. displayenv

D. man env

E. printenv

A. env & E. printenv

Which of the following is the default location of the Xorg configuration file?

A. /etc/X11/xorg.conf

B. /etc/X11/X.conf

C. /etc/X/xorg.conf

D. /etc/Xorg/X.conf

A. /etc/X11/xorg.conf

Which of the following commands will explicitly start a full X windows system session?

A. startx

B. xinit

C. X

D. startX

A. startx

After installing and enabling the latest accelerated video card driver, the system fails to start the X Window System on a reboot. Which of the following drivers is MOST likely to allow the system to start the GUI?

A. vesa

B. vega

C. xorg

D. krfb

A. vesa

Which of the following commands will cause gedit to use workstation1 for I/O?

A. DISPLAY=workstation1 gedit

B. CONNECT=workstation1 gedit

C. GRAPHICS=workstation1 gedit

D. CONSOLE=workstation1 gedit

A. DISPLAY=workstation1 gedit

Which of the following commands will show status information of the print queues?

A. lpstatus

B. showprint

C. lpqueue

D. lpstat

lpstat

Where is the default location of sendmail binary?

A. /usr/lib/sendmail

B. /etc/mail/sendmail

C. /var/spool/sendmail

D. /sbin/sendmail

A. /usr/lib/sendmail

Which of the following files holds information on the system's time zone?

A. /etc/timezone

B. /etc/localtime

C. /etc/time

D. /etc/localzone

B. /etc/localtime

Which of the following commands will show active network connections?

A. ipstat

B. ifstat

C. netstat

D. networkstat

C. netstat

A user has inserted a USB drive but it has not been automatically mounted. Which of the following commands will show the device name of the USB drive?

A. mount -t usb

B. fdisk -l

C. usb_scan

D. partprobe

B. fdisk -l

Which of the following will burn an ISO image to a writable SCSI CD-ROM drive located on SCSI address 0,1,0?

A. cdrecord -v -eject dev=0,1,0 data.iso

B. cdrecord -t scsi -eject -d=0,1,0 data.iso

C. cdrecord dev=0,1,0 -t=data.iso

D. cdrecord -V -dev 0,1,0 -eject data.iso

A. cdrecord -v -eject dev=0,1,0 data.iso

Which of the following /etc/fstab entries represents a Read-Write file system that can be mounted by any user?

A. /dev/hdc1 /data ext3 noauto,users 0 0

B. /dev/hdc1 /data auto defaults 0 0

C. /dev/hdc1 /data auto noauto,user 0 0

D. /dev/hdc1 /data ext3 defaults 0 0

A. /dev/hdc1/data ext3 noauto,users 0 0

A technician wants to upgrade an existing package to a new software package called software.rpm. Which of the following commands will accomplish this?

A. rpm -el ./software.rpm

B. rpm -Ve ./software.rpm

C. rpm -ieh ./software.rpm

D. rpm -Uvh ./software.rpm

D. rpm -Uvh ./software.rpm

Which of the following is the correct way to upgrade an existing software package using yum?

A. yum new package

B. yum get package

C. yum retrieve package

D. yum update package

D. yum update package

Which of the following key commands in vi allows a technician to append to the current line?

A. A

B. aa

C. p

D. a

A. A

Which of the following commands will replace the first instance of the string "linux" to "Linux" in the text file called history.txt and outputs the results to standard output?

A. sed r/linux/Linux/ history.txt

B. sed g/linux/Linux/ history.txt

C. sed s/linux/Linux/ history.txt

D. sed w/linux/Linux/ history.txt

C. sed s/linux/Linux/ history.txt

Which of the following symbols redirects standard output?

A. <

B. =

C. &

D. >

D. >

Which of the following commands will allow an administrator to change the priority of a running process?

A. bg

B. pstree

C. renice

D. fg

C. renice

Which of the following is the BEST way to direct the standard output of a program to both the screen and a file at the same time?

A. cat

B. tee

C. redirection (>)

D. echo

B. tee

If you want to change profiles for all users on the system.

/etc/profile and /etc/bashrc

When the user logins in, specific user.

.bash_profile

When the user starts a new shell, specific user.

.bashrc

How to unassign the variable COLOR?

unset COLOR

To see all the functions on your system?

set

Which file specifies the environment variables to be set.

/etc/security/pam_env.conf

If you want a new file to be created when a new user is created, where do you put it ?

/etc/skel

Which file that specifies the skeleton file, the shell and the default home when a new user is created?

/etc/default/useradd

Where is the printer queue stored ?

/var/spool/cups

How can you configure cups graphically?

http://localhost:631/

Two most important files for configuring cups?

/etc/cups/printers.conf & /etc/cups/cupsd.conf

how to add a printer?

lpadmin -p printername -E -v device -m name_of_ppd

show available devices for a printer?

lpinfo -v

make a default printer

lpadmin -d textprinter

To print something?

lpr -Ptextprinter file_to_print

Configuring a Text Only Printer

$ lpadmin -p textprinter -m textonly.ppd

what is happening in the queue ?

$ lpq -Ptextprinter

To remove the last printer job

lprm

To remove all the printer jobs

lprm -

log files for cups ?

/var/logs/cups/error_log & /var/logs/cups/access_log

How to disable and enable printers?

cupsdisable dummyprinter

cupsenable dummyprinter

command allows a user to administer his/her own group

membership list without the requirement of superuser privileges.

groupmems

How to find files that has SUI set.

$ find / -perm /4000

To scan the entire network using nmap

nmap 8.8.8.8/24

which file can you limit the number of processes for a user or group?

/etc/security/limits.conf

which show you when is the last time a user has logged into or never logged into the system.

lastlog

which old method to allow and deny hosts?

/etc/hosts.allow & /etc/hosts.deny

$ ls -lZ

this will show if the file is handled under selinux

How to search for SElinux related issues in the logs?

$ grep AVC | /var/log/audit/audit.log

Which command you can use to schedule a job at a later time, just once?

at 9:30 PM Tue

warning: commands will be executed using /bin/sh

at> echo "Well gosh golly, it's 9:30 PM on Tuesday."

at> ^D

Which file you can use to schedule cron jobs?

/etc/crontab

What is the format of the lines in /etc/crontab?

* user command

min hour day mon dow

files to allow users to user or not to use at or cron?

/etc/at.deny

/etc/at.allow

/etc/cron.deny

/etc/cron.allow

What can schedules job within a specific time frame?

/etc/anacrontab

what is the most trusted stratum number?

ntp uses stratum (highest trusted in stratum 1).

how to set date?

date -s 9:15

or

timedatectl set-time 9:15

how to synchronize hardware and system clock?

$ hwclock --hctosys

$ hwclock --systohc

which file that you can check for zone information?

/usr/share/zoneinfo

log files are typically stored where?

/var/log

what service will allow you to take care of when logs are deleted and stuff like that ?

/etc/logrotate.conf

where is the syslog confiigration file?

/etc/rsyslog.conf

Not every service logs to syslog.

local1-7 is used for that service.

Apache and Samba are among those servers.

Apache: Errorlog syslog:local1

new logging system for systemd systems.

journald and works hand in hand with rsyslog

journalctl

bring a network interface up or down

ifconfig enps035 down

assign an interface ip address or netmask

ifconfig enps035 192.168.1.100

ifconfig enps3045 netmask 255.255.0.0

most important file for network configuration

/etc/sysconfig/network-scripts

On Debian systems:

/etc/network/interfaces

show interfaces status

ip link show

or

ip addr show

static ip addressing or dhcp

BOOTPROTO = none or dhcp

Configuring Client Side DNS

/etc/resolv.conf

Received mail goes to

/var/spool/mail

Create E-mail Aliases

/etc/aliases

and exectue:

$ newaliases

so the changes take effect.

important file to configure email

/etc/postfix/master.cf

/etc/postfix/main.cf (queue directory where the messages will be stored).

what to do for email forwarding

set relayhost ip address in /etc/postfix/main.cf

configure ssh server

/etc/ssh/sshd_config

important options for ssh configuration

PermitRootLogin yes

PasswordAuthentication yes

X11Forwarding yes

UseDNS no

how to do SSH Tunneling

ssh -L 9000:ismvml61:443 aabdalma@ismnagios

AllowTcpForwarding yes

If you want to secure email messages and file transfers, you should use:

GnuPG

to generate keys:

gpg --gen-key

results will be in stored in: ~/.gnupg directory

gpg.pub

gpg --{sign|clearsign) originalfile

For an increased of security, we use -sign

--armor if you intend to the send the key over by email.

this checks for null. shell script

if [ -z $1 ]

variable that captures all the arguments as one entity?

$*

variable that captures all the arguments as one by one

$@

variable that captures all the number of arugments

$#

variable the capture the return value from a program

$?

send email to the root

[ -e $1 ] || mail -s "$1 does not exist" root < .

The ........ utility is an old utility for keyboard accessibility.

accessx

keyboard tool for GNOME

gok

keyboard tool for KDE

kmag

tool for speech in GNOME

Ocra

what tool covert desktop display to speech

Emacspeak

Tool to help the blind

brltty

to set french:

$ LANG=fr_FR.UTF-8

mysql commands to remember:

mysql_secure_installation

mysql -u root -p

$ create USER julia@'%' IDENTIFIED BY 'secret';

$ GRANT SELECT,INSERT,UPDATE, DELETE on videos.* TO julia@'%';

$ FLUSH PRIVILEGES;

how to initialize an X session

startx

which command to configure X?

$ Xorg -configure

Where do video drivers reside?

/usr/X11R6/lib/modules/drivers

or

/usr/lib/xorg/modules/drivers

command to set resolution

xrandr

too much information about X

xdpyinfo

information about current settings and positioning of an X window.

xwininfo

where the fonts at?

/usr/share/fonts

/usr/share/X11/fonts

fast and lightweight display manager.

lightdm

/usr/share/lightdm/lightdm.conf.d

index file for fonts in the current directory

mkfontscale

mkfontdir