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Linux Master 2· AssociateWeek 7 · Day 5~18 min read

Day 5 - Week 7 Comprehensive Review: Packages and Devices

📌 Key Takeaways

The RPM family is Red Hat, CentOS, Fedora, SUSE, and the DEB family is Debian, Ubuntu, Mint.
Low-level tools (rpm, dpkg) cannot resolve dependencies, and high-level tools (yum, apt) can.
apt update refreshes the list, and apt upgrade does the actual update.
A block device is b (disk) and a character device is c (keyboard, printer).
Three names — CUPS (printer) · ALSA (sound) · SANE (scanner).

Key Points Diagram

   Packages
     RPM family   Red Hat · CentOS · Fedora · SUSE      .rpm
       low-level  rpm   -i install · -U upgrade · -e erase · -q query
       high-level yum → dnf     SUSE uses zypper
       repository /etc/yum.repos.d/
 
     DEB family   Debian · Ubuntu · Mint                .deb
       low-level  dpkg  -i install · -r remove · -P purge · -l list
       high-level apt   update (list) → upgrade (actual)
       repository /etc/apt/sources.list
 
     Source install   tar extract → ./configure → make → make install
     Bundle/compress  tar (-c bundle -x extract -f file) + -z gzip · -j bzip2 · -J xz
 
   Devices
     /dev       b block (disk · USB · CD)   c character (keyboard · printer · terminal)
                major number (driver) · minor number (which one)
     Names      /dev/sda1   sd=SATA · a=first disk · 1=first partition
     udev       auto-creates/deletes /dev files when devices connect/disconnect
     Queries    lsblk · lsusb · lspci · lsmod · dmesg
 
   Peripherals
     Printer  CUPS  Common Unix Printing System   port 631 · cupsd.conf
              BSD  lpr · lpq · lprm
              SysV lp  · lpstat · cancel
     Sound    OSS → ALSA  Advanced Linux Sound Architecture   alsamixer
     Scanner  SANE  Scanner Access Now Easy       scanimage · xsane

Contrasting the Confusing Pairs

Item	A	B	Deciding criterion
RPM vs DEB	Red Hat · CentOS · SUSE	Debian · Ubuntu · Mint	Distribution lineage
Low-level vs high-level	`rpm` · `dpkg`	`yum` · `apt`	Whether it resolves dependencies
`rpm -i` vs `-U`	Install only	Installs too if absent	Handling of an existing version
`dpkg -r` vs `-P`	Keeps config	Deletes config too	Whether it purges
`apt update` vs `upgrade`	List only	Actual update	What changes
`yum` vs `zypper`	Red Hat family	SUSE	Both RPM but different tool
`tar -c` vs `-x`	Bundle	Extract	Direction
`-z` vs `-j` vs `-J`	gzip	bzip2	xz (uppercase)
Block vs character device	`b` disk	`c` keyboard	Whether random access is possible
Major vs minor number	Driver	Which device	—
`sda` vs `sda1`	The whole disk	Partition 1	Presence of a number
`lpr` vs `lpq` vs `lprm`	Print	Check queue	Cancel
OSS vs ALSA	Old method	Current standard	Generation
CUPS vs SANE	Printer	Scanner	Target device

Commonly Missed Points

Ubuntu is in the RPM family → No. It is in the Debian family, so it uses .deb.
SUSE is in the DEB family → No. It is in the RPM family, only its tool is zypper.
rpm resolves dependencies for you → It cannot. The high-level tool (yum) does.
apt update upgrades packages → It refreshes the list only.
tar also compresses → It only bundles. Compression needs -z, -j, or -J attached.
Run make install first → The order is ./configure → make → make install.
A printer is a block device → It is a character device. Only the disk family is block.
/dev/sda1 is the whole first disk → The whole disk is /dev/sda, and sda1 is a partition.
CUPS is the scanner → It is the printer. The scanner is SANE.
ALSA is the old one → OSS is the old one, and ALSA is the current standard.

Values That Appear on the Exam as They Are

Value	What it is
631	CUPS web admin port (IPP standard port)
`/etc/cups/cupsd.conf`	CUPS main config file
`/etc/yum.repos.d/`	YUM repository config location
`/etc/apt/sources.list`	APT repository config file
`b` / `c`	Block device / character device marker
`/etc/udev/rules.d/`	udev rule file location

Abbreviation	Full name
CUPS	Common Unix Printing System
ALSA	Advanced Linux Sound Architecture
SANE	Scanner Access Now Easy
OSS	Open Sound System
IPP	Internet Printing Protocol

Putting the Four Tools on One Line

Until yesterday we looked at each family separately. The exam mixes the four commands that do the same job into one set of choices, so you need practice reading across.

Task	`rpm`	`yum`	`dpkg`	`apt`
Install	`-i file.rpm`	`install name`	`-i file.deb`	`install name`
Remove	`-e name`	`remove name`	`-r name`	`remove name`
Remove including config	—	—	`-P name`	`purge name`
Installed list	`-qa`	`list installed`	`-l`	`list --installed`
Package info	`-qi name`	`info name`	`-s name`	`show name`
List of installed files	`-ql name`	—	`-L name`	—
Which package owns a file	`-qf file`	`provides file`	`-S file`	—
Search	—	`search keyword`	—	`search keyword`
Upgrade everything	—	`update`	—	`update` then `upgrade`

Reading vertically, there is a rule. The two low-level tools (rpm, dpkg) use hyphen options, and the two high-level tools (yum, apt) use English words. Low-level install takes a file, and the others take a name.
Reading horizontally, there are traps. Removal is -e for rpm and -r for dpkg. The list is -qa for rpm and -l for dpkg.

Same Letter, Different Meaning

Letter	Here	There
`-l`	`dpkg -l` — list of installed packages	`rpm -ql` — list of files inside the package
`-L`	`dpkg -L` — list of files inside the package	`scanimage -L` — list of scanners
`-i`	`rpm -i` · `dpkg -i` — install	`rpm -qi` — info (after q it means info)
`-P`	`dpkg -P` — purge	`lpr -P` — specify printer
`-r`	`dpkg -r` — remove	`tar -r` — append to an archive
`-x`	`tar -x` — extract	`lpadmin -x` — delete a printer
`-d`	`lp -d` — the printer to print to	`lpadmin -d` — set the default printer, `gzip -d` — decompress
`update`	`apt update` — list only	`yum update` — actual upgrade

Option letters are defined separately for each command, so they do not carry over. First look at "which command's option is it", then read the meaning.

Identifying from Just One Line

What is in front of you	Identification	Basis
`vsftpd-3.0.2-29.el7.x86_64.rpm`	RPM family, for the Red Hat 7 line, 64-bit	Extension `.rpm`, `el7`, `x86_64`
`vsftpd_3.0.5-0ubuntu1_amd64.deb`	DEB family, 64-bit	Extension `.deb`, underscore separators, `amd64`
`backup.tar.bz2`	Extract with `tar -jxvf`	`.bz2` is bzip2 → `-j`
`source.tar.xz`	Extract with `tar -Jxvf`	`.xz` → uppercase `-J`
`data.tgz`	Extract with `tar -zxvf`	`.tgz` is short for `.tar.gz`
`brw-rw----. 1 root disk 8, 17 …`	Block device, partition 1 of the second disk	Leading `b`, minor number 16 + 1
`crw-rw-rw-. 1 root root 1, 3 …`	Character device (`/dev/null`)	Leading `c`
`/dev/sdc2`	Partition 2 of the third disk	`c` = third, `2` = partition
`/dev/sr0`	The first CD/DVD drive	`sr`, numbering from 0
`ii apache2 …`	A properly installed package	`ii` in `dpkg -l`
`rc vsftpd …`	A package that was removed but whose config remains	`rc` in `dpkg -l` → finish removal with `dpkg -P`
`error: Failed dependencies:`	Install with a low-level tool got blocked by dependencies	Install with `yum` or `apt`

Choosing a Command from a Situation

Situation	What to choose	Confusing wrong answer
Which package `/usr/sbin/sshd` came from (Red Hat)	`rpm -qf /usr/sbin/sshd`	`rpm -ql` — the direction is opposite
The same question (Ubuntu)	`dpkg -S /usr/sbin/sshd`	`dpkg -L` — the direction is opposite
See the files inside a downloaded `.rpm` before installing	`rpm -qpl file.rpm`	`rpm -ql` — it only looks at installed ones
Update only what is already installed, and do not install what is absent	`rpm -Fvh *.rpm`	`rpm -Uvh` — it installs if absent
On Ubuntu, remove a package and its config too	`apt purge` · `dpkg -P`	`apt remove` · `dpkg -r`
Only see what is inside a `.tar.gz`	`tar -ztvf`	`tar -zxvf` — it actually extracts it
You plugged in a USB and do not know the device name	End of `dmesg`, `lsblk`	`lsusb` — it only tells you whether it is connected
See what chip a network card is	`lspci`	`lsusb` — PCI devices do not appear
Print 2 copies to printer `hp1` with a System V command	`lp -d hp1 -n 2 file`	`lpr -P hp1 -# 2 file` — that is the BSD way
Cancel waiting print job 7 with a BSD command	`lprm 7`	`lpq` — it only displays
Unmute with a single command line	`amixer set Master unmute`	`alsamixer` — it brings up a screen
See whether a scanner was picked up by SANE	`scanimage -L`	`lpstat -p` — that is for printers

Daemons · Config Files · Ports at a Glance

Target	Daemon	Config location	Port
YUM	None	`/etc/yum.conf`, `/etc/yum.repos.d/`	—
APT	None	`/etc/apt/sources.list`	—
Device file management	`systemd-udevd` (udev)	`/etc/udev/rules.d/`	—
Printing (CUPS)	`cupsd`	`/etc/cups/cupsd.conf`	631
Printing (old LPD)	`lpd`	`/etc/printcap`	515
Sound (ALSA)	None — kernel driver	`/etc/asound.conf`	—
Scanner (SANE)	`saned` (only for sharing)	`/etc/sane.d/`	6566

Among these, the port to memorize as a value is CUPS's 631. Also note that package tools and ALSA are not daemons, so they have no port.

Old	New	What changed
`yum`	`dnf`	The next generation of the same RPM family. The command structure is nearly the same
`apt-get` · `apt-cache`	`apt`	The split commands merged into one
`devfs` · pre-made device files	`udev`	Creates on connection and deletes on removal
`/dev/hda` (IDE)	`/dev/sda`	Disk naming rule
LPD · LPRng	CUPS	IPP, web admin page
OSS	ALSA	A Linux-only sound architecture

Connecting It All in One Pass — Attaching a Printer to a New Server

This week's three topics actually connect in one line.

   1  yum install cups              package — the high-level tool installs the dependencies too
   2  rpm -ql cups | grep conf      package — where were the config files installed (/etc/cups/cupsd.conf)
   3  systemctl start cups          start the cupsd daemon
   4  (connect the USB printer)
   5  dmesg | tail                  device — did the kernel recognize it
   6  lsusb                         device — does it show in the USB list
   7  ls -l /dev/usb/lp0            device — the character device file udev made (leading c)
   8  http://localhost:631          peripheral — register the printer on the web page
   9  lpr -P printer1 test.txt      peripheral — print
  10  lpq -P printer1               peripheral — check the queue

Steps 1-3 are software installation, 5-7 are device setup, and 8-10 are peripheral use. This is how the two exam-scope items "software installation" and "device setup" interlock.

That wraps up the first subject of the Level 2 exam, Linux Operation and Management. Starting next week we move into the second Level 2 subject, Linux Utilization — X Window, Internet usage, and application areas.

📖 Glossary

Dependency: The relationship with other packages that a package needs in order to work.
Low-level / high-level tools: A tool that handles a single file / a tool that uses repositories and handles dependencies too.
Block device / character device: A device with random access in blocks / a device processed sequentially one character at a time.
udev: The system that detects device connection and removal and automatically manages /dev files.
CUPS / ALSA / SANE: The standard systems responsible for printers / sound / scanners.
Spool: Jobs piled up in the print queue.
Repository: The server from which high-level tools fetch packages. yum puts addresses in /etc/yum.repos.d/, and apt in /etc/apt/sources.list.
purge: Removing a package along with its config files. dpkg -P, apt purge.

📝 Practice Questions

Click a choice to reveal the answer and explanation.

Question 1

Which of the following is a Debian-family distribution?

Question 2

Which command extracts a gzip-compressed archive with tar?

Question 3

Which command shows the full list of installed RPM packages?

Question 4

Which character appears at the very start of the ls -l /dev/sda result?

Question 5

Which BSD-family command cancels a print job that is waiting?

Question 6

Which of the following is the sound system currently used as the standard on Linux?

Official references

Linux Master 2 official exam syllabus(opens in a new tab)