Lesson 9: Managing Devices

Question 1

What folder is the hardware mapped to?

Answer 1

in the /dev folder

Question 2

What does the udev service do?

Answer 2

service udev identifies the attached hardware, sticks a name to it and maps to the /dev folder

Question 3

How do you override a devices assigned name?

Answer 3

rules.d which contains rules that override udev naming convention, you can find udev configuration in /etc/udev. For override settings to take place you can reboot system, unplug and plug back in the device or force udev to update and reapply rules – use the utility “udevadm control –reload-rules” then udevadm trigger

Question 4

How would you confirm that the system detected hardware properly?

Answer 4

When hardware is detected it will be present in the /sys folder (a virtual folder).

In /sys/dev you’ll see block (drivers) and char (tape)

In /sys/devices you’ll see additional devices

Question 5

How would you list specify hardware such as all pci devices?

Answer 5

You can simple do ls{device_type}

lspci which will list all pci devices
lsusb to list all usb devices

Question 6

How will dmesg help you troubleshoot hardware not being detected ?

Answer 6

will show you a log of loaded hardware from boot

dmesg {pipe} {less}

timestamp = the number of seconds since the kernel loaded

Question 7

How would you watch the system for any real time hardware changes?

Answer 7

Use the command

dmesg –follow OR dmesg -w

udevadm monitoring

dmidecode

note. to add to a text file try dmidecode > -/file_name.txt

Question 8

What is CUPS?

Answer 8

CUPS is a print management system for Linux that enables a computer to function as aprint server.

Question 9

How do you install CUPS?

Answer 9

Install cups -> yum list cups
-> systemectl enable –now cups
to verify status -> systemctl status cups

note. CUPS install a web interface. Navigate to locale host @ 127.0.0.1:631

Question 10

How do you add printers ?

Answer 10

You can add printer from the CUPS web interface

note. CUPS install a web interface. Navigate to locale host @ 127.0.0.1:631 lpadmin -h localhost -p {printer name} -E (to enable) -v socket://{IP_address} -P {ppd_file_path}

Question 11

How do you print?

Answer 11

lp -d {printer_name} {file_to_print} OR lpr print

Question 12

How do you check the status of a print job?

Answer 12

lpstat -p {printer_name} OR lpq

Question 13

How to set a default printer?

Answer 13

LPDEST={printer_name}

test. echo $LPDEST

Question 14

What is the lpr command?

Answer 14

The lpr command submits files for printing. The syntax of the lpr command is lpr [options] [file names]

• E Force encryption when connecting to the server.
• P {destination} Send the print job to the destination printer specified.
• # {copies} Set the number of copies to print from 1 to 100.
• T {name} Set the job name.
• l Specify that the print file is already formatted and should be sent to the destination without being filtered.
• o {option} Set a job option, like printing in landscape mode, scaling the printed output, printing double-sided, etc. Job optionsvary depending on the printer.
• p Print the specified files with a shaded header that includesthe date, time, job name, and page number.
• r Specify that the printed files should be deleted afterprinting.

Question 15

How do you cancel a print job

Answer 15

cancel {print_job_ID} OR lprm {print_job_ID}

Question 16

What is GPIO?

Answer 16

General-purpose input/output (GPIO) refers to pins on a circuit board that have nodesignated purpose, but are controllable by the user at runtime.

Question 17

What is the Isdev command?

Answer 17

The lsdev command displays various information about a system’s hardware asreported by the kernel. It compiles this information from three files in the /proc/directory:

/interrupts

/ioports

/dma

Question 18

System logs that record a “Machine Check Exception” error message usually indicate what type of issue?

Answer 18

An issue with RAM. The mcelog command can retrieve and print these error messages for easier analysis.

note. To confirm RAM module failure, you can use utilities like MemTest, MemTest86+, andmemtester to perform a stress test on all RAM modules for several hours, reportingany errors that are encountered.

Question 19

What command lists each detected hardware component on the system and provides details about each device?

Answer 19

The lshw command, the syntax of the lshw command is lshw [options]

Question 20

What does the dmidecode command do?

Answer 20

The dmidecode command dumps the system’s Desktop Management Interface(DMI) table and presents it in a human-readable format. The syntax of the dmidecode command is dmidecode [options]