Fedora 30 : The paris-traceroute tool.

Today I tested two Linux tools named:paris-traceroute. This tool can be install with dnf tool. This tool named paris-traceroute was implemented by Xavier Cuvellier. Debugged and enhanced by Brice Augustin. The techniques invented by the authors of Paris-traceroute to enumerate the paths of ECMP flow-based load balancing. I used the 8.8.8.8 address to test this tool.

[root@desk mythcat]# paris-traceroute 8.8.8.8 -p icmp
...
[root@desk mythcat]# paris-traceroute 8.8.8.8 -i
...
[root@desk mythcat]# paris-traceroute 8.8.8.8 -l
...

Using the verbose mode the tool will print debug messages:

[root@desk mythcat]# paris-traceroute 8.8.8.8 -v
[DEBUG](Options.cc, 222)dst_addr = 8.8.8.8
[DEBUG](Options.cc, 340)protocol     = udp
[DEBUG](Options.cc, 341)src_add      = 
[DEBUG](Options.cc, 342)dst_addr     = 8.8.8.8
[DEBUG](Options.cc, 343)ttl_initial  = 1
[DEBUG](Options.cc, 344)ttl_max      = 30
[DEBUG](Options.cc, 345)tos          = 0
[DEBUG](Options.cc, 346)probe_length = 0
[DEBUG](Options.cc, 347)algo         = hopbyhop
[DEBUG](Options.cc, 348)timeout      = 5000
[DEBUG](Options.cc, 349)delay        = 50
[DEBUG](Options.cc, 350)max_try      = 3
[DEBUG](Options.cc, 351)max_missing  = 3
[DEBUG](Options.cc, 352)id_initial   = 1
[DEBUG](Options.cc, 353)resolve      = true
[DEBUG](Options.cc, 354)ipid         = false
[DEBUG](Util.cc, 246)p_proto = 1
[INFO](Server.cc, 216)waiting for the first packet..

[INFO](TracertImpl.cc, 48)HopByHop algo
[INFO](TracertImpl.cc, 183)Send probe, ttl=1, id=1
[DEBUG](UDPProbe.cc, 247)==> UDP Probe :
[DEBUG](IP4Header.cc, 346)IP4 header :
[DEBUG](IP4Header.cc, 347)tos                = 0
[DEBUG](IP4Header.cc, 348)total_length       = 30
[DEBUG](IP4Header.cc, 349)ttl                = 1
[DEBUG](IP4Header.cc, 350)protocol           = 17
[DEBUG](IP4Header.cc, 353)source_address     = 
[DEBUG](IP4Header.cc, 355)dest_address       = 8.8.8.8
[DEBUG](UDPHeader.cc, 143)UDP header :
[DEBUG](UDPHeader.cc, 144)source_port        = 
[DEBUG](UDPHeader.cc, 145)dest_port          = 
[DEBUG](UDPHeader.cc, 146)datagram_length    = 10
[DEBUG](UDPHeader.cc, 147)checksum           = 12584
[DEBUG](UDPProbe.cc, 250)Data :
[DEBUG]0x01 0x00 
[DEBUG]0x45 0x00 0x00 0x1e 0x00 0x01 0x00 0x00 
[DEBUG]0x01 0x11 0x00 0x00 0xc0 0xa8 0x00 0x8f 
[DEBUG]0x08 0x08 0x08 0x08 0x82 0xb0 0x82 0xb1 
[DEBUG]0x00 0x0a 0x28 0x31 0x01 0x00 
[INFO](Server.cc, 276)Captured first packet!

[DEBUG](Server.cc, 280)Incoming message :
[DEBUG](Server.cc, 281)parsing.. ef72baa0 58
[DEBUG]0x45 0xc0 0x00 0x3a 0x5c 0xcd 0x00 0x00 
[DEBUG]0x40 0x01 0x9b 0x55 0xc0 0xa8 0x00 0x01 
[DEBUG]0xc0 0xa8 0x00 0x8f 0x0b 0x00 0xc6 0x62 
[DEBUG]0x00 0x00 0x00 0x00 0x45 0x00 0x00 0x1e 
[DEBUG]0x00 0x01 0x00 0x00 0x01 0x11 0xe8 0x87 
[DEBUG]0xc0 0xa8 0x00 0x8f 0x08 0x08 0x08 0x08 
[DEBUG]0x82 0xb0 0x82 0xb1 0x00 0x0a 0x28 0x31 
[DEBUG]0x01 0x00 
[DEBUG](Server.cc, 285)Incoming message parsed :
[DEBUG](IP4Header.cc, 346)IP4 header :
[DEBUG](IP4Header.cc, 347)tos                = 192
[DEBUG](IP4Header.cc, 348)total_length       = 58
[DEBUG](IP4Header.cc, 349)ttl                = 64
[DEBUG](IP4Header.cc, 350)protocol           = 1
[DEBUG](IP4Header.cc, 353)source_address     = 
...

You can see more about this tool here. Another tool is dublin-traceroute works like paris-traceroute but introduces a new technique for NAT detection ( this is not in the Fedora repo).

Fedora 30 : A general intro to linux signals with python.

UNIX/Linux systems offer special mechanisms to communicate between each individual process with signals. Let's see these signals:

[mythcat@desk ~]$ kill -l
 1) SIGHUP  2) SIGINT  3) SIGQUIT  4) SIGILL  5) SIGTRAP
 6) SIGABRT  7) SIGBUS  8) SIGFPE  9) SIGKILL 10) SIGUSR1
11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM
16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP
21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ
26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO 30) SIGPWR
31) SIGSYS 34) SIGRTMIN 35) SIGRTMIN+1 36) SIGRTMIN+2 37) SIGRTMIN+3
38) SIGRTMIN+4 39) SIGRTMIN+5 40) SIGRTMIN+6 41) SIGRTMIN+7 42) SIGRTMIN+8
43) SIGRTMIN+9 44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12 47) SIGRTMIN+13
48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14 51) SIGRTMAX-13 52) SIGRTMAX-12
53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9 56) SIGRTMAX-8 57) SIGRTMAX-7
58) SIGRTMAX-6 59) SIGRTMAX-5 60) SIGRTMAX-4 61) SIGRTMAX-3 62) SIGRTMAX-2
63) SIGRTMAX-1 64) SIGRTMAX

Each signal is represented by an integer value, and the list of signals that are available. This simple python script create a process and print one message. Each process named PID comes with a number.

[mythcat@desk ~]$ cat python3 signal_001.py 
cat: python3: No such file or directory
import os
import sys
import time
print('PID number is:', os.getpid())
while True:
    print('Waiting...')
    time.sleep(6)

[mythcat@desk ~]$ python3 signal_001.py 
PID number is: 2566
Waiting...
Waiting...
Waiting...
Waiting...
Waiting...
Hangup

The PID process can be kill with this command:

[mythcat@desk ~]$ kill -SIGTERM 2566

Let's see another example that receives the signal we have sent to the process.

import os
import signal
import time

def receiveSignal(signalNumber, frame):
    print('Received:', signalNumber)
    raise SystemExit('Exiting')
    return

if __name__ == '__main__':
    # register the signals to be caught
    signal.signal(signal.SIGHUP, receiveSignal)
    signal.signal(signal.SIGINT, receiveSignal)
    signal.signal(signal.SIGQUIT, receiveSignal)
    signal.signal(signal.SIGILL, receiveSignal)
    signal.signal(signal.SIGTRAP, receiveSignal)
    signal.signal(signal.SIGABRT, receiveSignal)
    signal.signal(signal.SIGBUS, receiveSignal)
    signal.signal(signal.SIGFPE, receiveSignal)
    #signal.signal(signal.SIGKILL, receiveSignal)
    signal.signal(signal.SIGUSR1, receiveSignal)
    signal.signal(signal.SIGSEGV, receiveSignal)
    signal.signal(signal.SIGUSR2, receiveSignal)
    signal.signal(signal.SIGPIPE, receiveSignal)
    signal.signal(signal.SIGALRM, receiveSignal)
    signal.signal(signal.SIGTERM, receiveSignal)
    # register the signal to be caught
    signal.signal(signal.SIGUSR1, receiveSignal)

    # register the signal to be ignored
    signal.signal(signal.SIGINT, signal.SIG_IGN)

    # output current process id
    print('My PID is:', os.getpid())

    signal.pause()

Let't run it and see what happend when send a signal to the PID:

[mythcat@desk ~]$ python3 py_pid.py
My PID is: 2698
Received: 10
Exiting

You can see the kill command will send this output: Received: 10 Exiting .

[mythcat@desk ~]$ kill -SIGUSR1 2698

Fedora 30 : Detect hardware issues.

You can detect your hardware and read the health of your system using many commands and tools.
Today I show you these tools: lm_sensors-sensord.x86_64 and lshw.

[root@desk mythcat]# dnf install lm_sensors-sensord.x86_64 
...
Installed:
  lm_sensors-sensord-3.5.0-6.fc30.x86_64       rrdtool-1.7.2-1.fc30.x86_64      
  libdbi-0.9.0-13.fc30.x86_64                 

Complete!
...
[root@desk mythcat]# dnf install lshw
Last metadata expiration check: 0:50:16 ago on Sun 22 Sep 2019 10:27:55 PM EEST.
Dependencies resolved.
================================================================================
 Package       Architecture    Version                   Repository        Size
================================================================================
Installing:
 lshw          x86_64          B.02.18-21.fc30           updates          315 k

Transaction Summary
================================================================================
Install  1 Package

Total download size: 315 k
Installed size: 1.1 M
Is this ok [y/N]: y
Downloading Packages:
lshw-B.02.18-21.fc30.x86_64.rpm                 598 kB/s | 315 kB     00:00    
--------------------------------------------------------------------------------
Total                                            56 kB/s | 315 kB     00:05     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1 
  Installing       : lshw-B.02.18-21.fc30.x86_64                            1/1 
  Running scriptlet: lshw-B.02.18-21.fc30.x86_64                            1/1 
  Verifying        : lshw-B.02.18-21.fc30.x86_64                            1/1 

Installed:
  lshw-B.02.18-21.fc30.x86_64                                                   

Complete!

First, use this command to select and setup the sensors:

[root@desk mythcat]# sensors-detect
# sensors-detect revision $Revision$
# System: Gigabyte Technology Co., Ltd. Z68P-DS3
# Kernel: 5.2.13-200.fc30.x86_64 x86_64
# Processor: Intel(R) Celeron(R) CPU G1620 @ 2.70GHz (6/58/9)

This program will help you determine which kernel modules you need
to load to use lm_sensors most effectively. It is generally safe
and recommended to accept the default answers to all questions,
unless you know what you're doing.

Some south bridges, CPUs or memory controllers contain embedded sensors.
Do you want to scan for them? This is totally safe. (YES/no): YES
...

Driver `coretemp':
  * Chip `Intel digital thermal sensor' (confidence: 9)

Driver `it87':
  * ISA bus, address 0x290
    Chip `ITE IT8728F Super IO Sensors' (confidence: 9)

Do you want to overwrite /etc/sysconfig/lm_sensors? (YES/no): YES
Unloading i2c-dev... OK

The output of sensors can be show like this:

[root@desk mythcat]# sensors
it8728-isa-0290
Adapter: ISA adapter
in0:          +1.04 V  (min =  +0.00 V, max =  +3.06 V)
in1:          +2.00 V  (min =  +0.00 V, max =  +3.06 V)
in2:          +2.98 V  (min =  +0.00 V, max =  +3.06 V)
in3:          +2.96 V  (min =  +0.00 V, max =  +3.06 V)
in4:          +0.00 V  (min =  +0.00 V, max =  +3.06 V)  ALARM
in5:          +0.70 V  (min =  +0.00 V, max =  +3.06 V)
in6:          +1.52 V  (min =  +0.00 V, max =  +3.06 V)
3VSB:         +3.38 V  (min =  +0.00 V, max =  +6.12 V)
Vbat:         +3.00 V  
fan1:        1180 RPM  (min =    0 RPM)
fan2:           0 RPM  (min =    0 RPM)
fan3:           0 RPM  (min =    0 RPM)
fan4:           0 RPM  (min =    0 RPM)
temp1:        +37.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = thermistor
temp2:        +25.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = thermistor
temp3:        +25.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = Intel PECI
intrusion0:  ALARM

nouveau-pci-0500
Adapter: PCI adapter
GPU core:     +0.90 V  (min =  +0.85 V, max =  +1.00 V)
temp1:        +42.0°C  (high = +95.0°C, hyst =  +3.0°C)
                       (crit = +105.0°C, hyst =  +5.0°C)
                       (emerg = +135.0°C, hyst =  +5.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Package id 0:  +37.0°C  (high = +85.0°C, crit = +105.0°C)
Core 0:        +36.0°C  (high = +85.0°C, crit = +105.0°C)
Core 1:        +37.0°C  (high = +85.0°C, crit = +105.0°C)

Using the lshw tool:

[root@desk mythcat]# lshw
desk                        
    description: Desktop Computer
...

The tool extracts detailed information on the hardware configuration of the machine and output is shown like HTML, JSON or SQLite database, see the help:

       lshw [ -version ]

       lshw [ -help ]

       lshw [ -X ]

       lshw [  [ -html ]  [ -short ]  [ -xml ]  [ -json ]  [ -businfo ]  ]  [ -dump filename ]  [
       -class class... ]  [ -disable test... ]  [ -enable test... ]  [ -sanitize ]  [ -numeric  ]
       [ -quiet ]

Fedora 30 : Interactive learning and reinventing the wheel in programming.

Today I returned from an activity that prompted me to find a solution to display logos.
I found this GitHub repo that I read and then turned it into a single script.
It took about an hour.

Fedora 30 : A general purpose 3D CAD modeler.

I don't use the Computer-aided design (CAD) solutions but today I tested a good one with Fedora 30.
The FreeCAD application is an open source option product design.
This is available on Linux, Windows, Mac OS X+.
The full list with all features can be found at this wiki page.

[root@desk mythcat]# dnf search freecad
Last metadata expiration check: 0:14:20 ago on Sb 07 sep 2019 21:54:39 +0300.
======================== Name Exactly Matched: freecad =========================
freecad.x86_64 : A general purpose 3D CAD modeler
======================= Name & Summary Matched: freecad ========================
freecad-data.noarch : Data files for FreeCAD
[root@desk mythcat]# dnf install freecad.x86_64
Last metadata expiration check: 0:19:37 ago on Sb 07 sep 2019 21:54:39 +0300.
Dependencies resolved.
================================================================================
 Package               Arch   Version                             Repo     Size
================================================================================
Installing:
 freecad               x86_64 1:0.18.3-1.fc30                     updates  38 M
...

Complete!
[root@desk mythcat]# exit 
exit
[mythcat@desk ~]$ FreeCAD
FreeCAD 0.18, Libs: 0.18RUnknown
© Juergen Riegel, Werner Mayer, Yorik van Havre 2001-2019
  #####                 ####  ###   ####  
  #                    #      # #   #   # 
  #     ##  #### ####  #     #   #  #   # 
  ####  # # #  # #  #  #     #####  #   # 
  #     #   #### ####  #    #     # #   # 
  #     #   #    #     #    #     # #   #  ##  ##  ##
  #     #   #### ####   ### #     # ####   ##  ##  ## 

It seems to work very well.

Fedora 30 : Huion graphics tablet installation.

This is an old tutorial I wrote a few days ago. You need to install the last kernel driver development and dkms according to this website.

[root@desk mythcat]# dnf install -y "kernel-devel-uname-r == $(uname -r)"
Fedora Modular 30 - x86_64                                                          14 kB/s |  25 kB     00:01    
Fedora Modular 30 - x86_64 - Updates                                                28 kB/s |  23 kB     00:00    
google-chrome                                                                      8.8 kB/s | 1.3 kB     00:00    
RPM Fusion for Fedora 30 - Free - Updates                                           12 kB/s | 6.8 kB     00:00    
RPM Fusion for Fedora 30 - Free - Updates                                          338 kB/s | 341 kB     00:01    
RPM Fusion for Fedora 30 - Free                                                     34 kB/s |  11 kB     00:00    
RPM Fusion for Fedora 30 - Nonfree - Updates                                       8.7 kB/s | 6.6 kB     00:00    
RPM Fusion for Fedora 30 - Nonfree - Updates                                        50 kB/s |  45 kB     00:00    
RPM Fusion for Fedora 30 - Nonfree                                                  15 kB/s |  11 kB     00:00    
Fedora 30 - x86_64 - VirtualBox                                                    356  B/s | 181  B     00:00    
Package kernel-devel-5.2.9-200.fc30.x86_64 is already installed.
Dependencies resolved.
Nothing to do.
Complete!
[root@desk mythcat]# dnf install -y dkms
Last metadata expiration check: 0:01:10 ago on Sat 31 Aug 2019 12:29:01 PM EEST.
Package dkms-2.6.1-3.fc30.noarch is already installed.
Dependencies resolved.
Nothing to do.
Complete!

Let's see if this works:

[root@desk mythcat]# xinput
⎡ Virtual core pointer                          id=2    [master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
⎜   ↳ PixArt USB Optical Mouse                  id=8    [slave  pointer  (2)]
⎜   ↳ PenTablet  Pen (0)                        id=11   [slave  pointer  (2)]
⎣ Virtual core keyboard                         id=3    [master keyboard (2)]                                                
    ↳ Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]                                                
    ↳ Power Button                              id=6    [slave  keyboard (3)]                                                
    ↳ Power Button                              id=7    [slave  keyboard (3)]                                                
    ↳ AT Translated Set 2 keyboard              id=9    [slave  keyboard (3)]  

If not work test the modules:

[root@desk mythcat]# modprobe -r hid-kye hid-uclogic hid-polostar hid-viewsonic
modprobe: FATAL: Module hid-polostar not found.
[root@desk mythcat]# modprobe -r hid-kye hid-uclogic  hid-viewsonic

You can use the official GitHub project:

wget https://github.com/DIGImend/digimend-kernel-drivers/releases/download/v10/digimend-kernel-drivers-10.tar.gz
tar xf digimend-kernel-drivers-10.tar.gz
cd digimend-kernel-drivers-10
sudo dnf install -y "kernel-devel-uname-r == $(uname -r)" dkms
sudo make dkms_install

Fedora 30 : About the Jupyter lab tool.

The tutorial for today is about Jupiter Lab and Fedora 30. You can see an old tutorial with Fedora 29 here.
The JupyterLab is the next-generation web-based user interface for Project Jupyter.
This can be installed using conda, pip or pipenv.
I used pip3 tool for instalation process on Fedora 30 distro:

[mythcat@desk ~]$ pip3 install jupyterlab --user
...
Successfully installed Send2Trash-1.5.0 attrs-19.1.0 backcall-0.1.0 bleach-3.1.0 defusedxml-0.6.0 
ipykernel-5.1.2 ipython-7.8.0 ipython-genutils-0.2.0 jedi-0.15.1 json5-0.8.5 jsonschema-3.0.2 
jupyter-client-5.3.1 jupyter-core-4.5.0 jupyterlab-1.1.1 jupyterlab-server-1.0.6 mistune-0.8.4 
nbconvert-5.6.0 nbformat-4.4.0 notebook-6.0.1 pandocfilters-1.4.2 parso-0.5.1 pexpect-4.7.0 
pickleshare-0.7.5 prometheus-client-0.7.1 prompt-toolkit-2.0.9 ptyprocess-0.6.0 pyrsistent-0.15.4 
pyzmq-18.1.0 terminado-0.8.2 testpath-0.4.2 tornado-6.0.3 traitlets-4.3.2 wcwidth-0.1.7 
webencodings-0.5.1
[mythcat@desk ~]$ jupyter notebook --version
6.0.1

This tool browsers can be used with :Firefox, Chrome and Safari.
The tool can be start with this command:

[mythcat@desk ~]$ jupyter lab
[I 19:53:05.527 LabApp] Writing notebook server cookie secret to ...

The default browser will open a new tab and show the interface for this tool, see screenshot:
If you install a new python module then you need to close and reopen the tool.
You can run every row command with Shift+Enter keys.
When you want to close it just close the browser tab and press Ctrl+C keys.

Shutdown this notebook server (y/[n])? y
[C 20:09:00.058 LabApp] Shutdown confirmed
[I 20:09:00.304 LabApp] Shutting down 0 kernels

 To see additional kernels follow this link. The Fedora 30 comes with this kernels for Jupyter using the dnf tool:

[root@desk mythcat]# dnf search jupyter | grep kernel
Last metadata expiration check: 0:57:13 ago on Mi 04 sep 2019 19:46:15 +0300.
polymake-jupyter.noarch : Jupyter kernel for polymake
gap-pkg-jupyterkernel.noarch : Jupyter kernel written in GAP
python3-jupyter-c-kernel.noarch : Minimalistic C kernel for Jupyter
gap-pkg-jupyterkernel-doc.noarch : Jupyter kernel for GAP documentation
python3-jupyter-kernel-test.noarch : Machinery for testing Jupyter kernels via
python3-jupyroot.x86_64 : ROOT Jupyter kernel
python3-metakernel.noarch : Metakernel for Jupyter
python3-ipykernel.noarch : IPython Kernel for Jupyter
python3-octave-kernel.noarch : A Jupyter kernel for Octave
python3-metakernel-bash.noarch : A Bash kernel for Jupyter/IPython
python3-metakernel-python.noarch : A Python kernel for Jupyter/IPython
python3-spyder-kernels.noarch : Jupyter kernels for the Spyder console
python3-metakernel-echo.noarch : A simple echo kernel for Jupyter/IPython
R-IRkernel.noarch : Native R Kernel for the 'Jupyter Notebook'

Another feature of Jupyter is the ability to run it as a presentation server:

[mythcat@desk ~]$ jupyter nbconvert --generate-config
Writing default config to: /home/mythcat/.jupyter/jupyter_nbconvert_config.py
[mythcat@desk ~]$ cat /home/mythcat/.jupyter/jupyter_nbconvert_config.py
# Configuration file for jupyter-nbconvert.

#------------------------------------------------------------------------------
# Application(SingletonConfigurable) configuration
#------------------------------------------------------------------------------

## This is an application.

Change jupyter_nbconvert_config.py file by adding your settings. For example:

## Accept connections from all IPs
c.ServePostProcessor.ip = '*'

## Do not open the browser automatically
c.ServePostProcessor.open_in_browser = False

After you work with jupyter you can save it with a name like Test001 and run this command:

[mythcat@desk ~]$ jupyter nbconvert "Test001.ipynb" --to slides --post serve[NbConvertApp] 
Converting notebook Test001.ipynb to slides
[NbConvertApp] Writing 278626 bytes to Test001.slides.html
[NbConvertApp] Redirecting reveal.js requests to https://cdnjs.cloudflare.com/ajax/libs/reveal.js/3.5.0
Serving your slides at http://*:8000/Test001.slides.html
Use Control-C to stop this server

The result of the HTML presentation can be see at http://localhost:8000/Test001.slides.html#.

Fedora 30 : The last Krita version.

Today I will show you how to use the last version of Krita with Fedora 30 distro. First, download the app image application Krita from the official website. The AppImage is a format for distributing portable software on Linux without needing superuser permissions to install the application. In the folder where is the download you need to set it executable:

[mythcat@desk ~]$ chmod +x krita-4.2.5-x86_64.appimage 
[mythcat@desk ~]$ ./krita-4.2.5-x86_64.appimage 

This version 4.2.5 work very well with Fedora 30 distro.

Fedora 30 : Few commands for Fedora distro.

In this tutorial, I will show these commands for Fedora distro and what information can provide to users. First is lspci:

[root@desk mythcat]# lspci 
...
05:00.1 Audio device: NVIDIA Corporation High Definition Audio Controller (rev a1)
[root@desk mythcat]# echo 1 > /sys/bus/pci/devices/0000\:0
0000:00:00.0/ 0000:00:1b.0/ 0000:00:1c.4/ 0000:00:1f.2/ 0000:05:00.0/
0000:00:02.0/ 0000:00:1c.0/ 0000:00:1d.0/ 0000:00:1f.3/ 0000:05:00.1/
0000:00:16.0/ 0000:00:1c.2/ 0000:00:1e.0/ 0000:02:00.0/ 
0000:00:1a.0/ 0000:00:1c.3/ 0000:00:1f.0/ 0000:03:00.0/ 
[root@desk mythcat]# echo 1 > /sys/bus/pci/devices/0000\:05\:00.1/remove
[root@desk mythcat]# lspci 
...
05:00.0 VGA compatible controller: NVIDIA Corporation GT218 [GeForce 210] (rev a2)
[root@desk mythcat]# echo 1 > /sys/bus/pci/rescan
[root@desk mythcat]# lspci -x -s 05:00.0
05:00.0 VGA compatible controller: NVIDIA Corporation GT218 [GeForce 210] (rev a2)
00: de 10 65 0a 07 04 10 00 a2 00 00 03 01 00 80 00
10: 00 00 00 f9 0c 00 00 d0 00 00 00 00 0c 00 00 ee
20: 00 00 00 00 01 df 00 00 00 00 00 00 42 38 11 13
30: 00 00 00 00 60 00 00 00 00 00 00 00 0c 01 00 00

[root@desk mythcat]# lspci -x -s 05:00.1
05:00.1 Audio device: NVIDIA Corporation High Definition Audio Controller (rev a1)
00: de 10 e3 0b 06 00 10 00 a1 00 03 04 01 00 80 00
10: 00 00 00 fa 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 42 38 11 13
30: 00 00 00 00 60 00 00 00 00 00 00 00 05 02 00 00

The next is dmesg: This NVIDIA Audio Controller detection has this output on dmesg:

[root@desk mythcat]# dmesg | grep 05:00.1
[    0.375902] pci 0000:05:00.1: [10de:0be3] type 00 class 0x040300
[    0.375929] pci 0000:05:00.1: reg 0x10: [mem 0xfaffc000-0xfaffffff]
[    0.376002] pci 0000:05:00.1: enabling Extended Tags
[ 2077.961694] pci 0000:05:00.1: [10de:0be3] type 00 class 0x040300
[ 2077.961730] pci 0000:05:00.1: reg 0x10: [mem 0xfaffc000-0xfaffffff]
[ 2077.962138] pci 0000:05:00.1: BAR 0: assigned [mem 0xfa000000-0xfa003fff]
[ 2423.644523] pci 0000:05:00.1: [10de:0be3] type 00 class 0x040300
[ 2423.644559] pci 0000:05:00.1: reg 0x10: [mem 0xfa000000-0xfa003fff]
[ 2423.644968] pci 0000:05:00.1: BAR 0: assigned [mem 0xfa000000-0xfa003fff]
[ 2517.259902] pci 0000:05:00.1: [10de:0be3] type 00 class 0x040300
[ 2517.259939] pci 0000:05:00.1: reg 0x10: [mem 0xfa000000-0xfa003fff]
[ 2517.260342] pci 0000:05:00.1: BAR 0: assigned [mem 0xfa000000-0xfa003fff]

The echo command can show information or set some issues :

[root@desk mythcat]# echo 1 > /sys/bus/pci/devices/0000:05:00.1/remove
[root@desk mythcat]# lspci -x -s 05:00.1
[root@desk mythcat]# 

Let's see

[root@desk mythcat]# lspci -v | grep -A7 -i "audio"
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio 
Controller (rev 05)
        Subsystem: Gigabyte Technology Co., Ltd Device a002
        Flags: bus master, fast devsel, latency 0, IRQ 3
        Memory at fbff4000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [50] Power Management version 2
        Capabilities: [60] MSI: Enable- Count=1/1 Maskable- 64bit+
        Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
        Capabilities: [100] Virtual Channel
--
05:00.1 Audio device: NVIDIA Corporation High Definition Audio Controller (rev a1)
        Subsystem: eVga.com. Corp. Device 1311
        Flags: bus master, fast devsel, latency 0, IRQ 5
        Memory at faffc000 (32-bit, non-prefetchable) [size=16K]
        Capabilities: [60] Power Management version 3
        Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
        Capabilities: [78] Express Endpoint, MSI 00

The systemctl can help with Fedora settings:

[root@desk mythcat]# systemctl status alsa-state.service
● alsa-state.service - Manage Sound Card State (restore and store)
   Loaded: loaded (/usr/lib/systemd/system/alsa-state.service; static; vendor preset: disabled)
   Active: inactive (dead)
[root@desk mythcat]# systemctl start alsa-state.service
[root@desk mythcat]# systemctl status alsa-state.service
● alsa-state.service - Manage Sound Card State (restore and store)
   Loaded: loaded (/usr/lib/systemd/system/alsa-state.service; static; vendor preset: disabled)
   Active: active (running) since Thu 2019-08-29 13:53:58 EEST; 1s ago
 Main PID: 2951 (alsactl)
    Tasks: 1 (limit: 1942)
   Memory: 1.3M
   CGroup: /system.slice/alsa-state.service
           └─2951 /usr/sbin/alsactl -s -n 19 -c -E ALSA_CONFIG_PATH=/etc/alsa/alsactl.conf 
--initfile=/lib/alsa/init/00main >

Aug 29 13:53:58 desk systemd[1]: Started Manage Sound Card State (restore and store).
Aug 29 13:53:58 desk alsactl[2951]: alsactl 1.1.9 daemon started
Aug 29 13:53:58 desk alsactl[2951]: /usr/sbin/alsactl: load_state:1735No soundcards found...
[root@desk mythcat]# systemctl status alsa-restore.service
● alsa-restore.service - Save/Restore Sound Card State
   Loaded: loaded (/usr/lib/systemd/system/alsa-restore.service; static; vendor preset: disabled)
   Active: inactive (dead)
[root@desk mythcat]# systemctl start alsa-restore.service
[root@desk mythcat]# systemctl status alsa-restore.service
● alsa-restore.service - Save/Restore Sound Card State
   Loaded: loaded (/usr/lib/systemd/system/alsa-restore.service; static; vendor preset: disabled)
   Active: inactive (dead)

Aug 29 13:58:53 desk systemd[1]: Condition check resulted in Save/Restore Sound Card State being skipped.

The hostnamectl command for Fedora workstations:

[root@desk mythcat]# hostnamectl set-hostname  new_hostname

The last is the common dnf command:

[root@desk mythcat]# dnf

Fedora 30 : Rollback to Fedora 30.

In this tutorial, I will show you how to rollback from a bad distro update of Fedora 31 to the old one Fedora 30.
If you follow this tutorial and you got errors then your dnf tool will have problems with update process.
After I follow the tutorial I got many packages and errors.
I try to fix with this but not work:

[root@desk mythcat]# dnf system-upgrade download --refresh --releasever=31
--setopt=module_platform_id=platform:f31 --skip-broken
Before you continue to ensure that your system is fully upgraded by running "dnf
--refresh upgrade". Do you want to continue [y/N]: y
...

Because the Fedora 31 is not available I need to roll back to my old Fedora 30. This are steps I used to fix this issue:

[root@desk mythcat]# pkcon refresh force -c -1
[root@desk mythcat]# dnf --releasever=30 --allowerasing downgrade fedora
[root@desk mythcat]# dnf clean all --releasever=32
[root@desk mythcat]# dnf clean all --releasever=31
[root@desk mythcat]# dnf clean all --releasever=30

The pkcon tool refresh the cached information about available updates and set the maximum acceptable age for cached metadata, in seconds.
The option of dnf tool clean all --releasever=32 will clean all packages from fc32.
I used this command to see what packages with errors and the repo with problems:

[root@desk mythcat]# dnf --releasever=30 --allowerasing downgrade fedora
...

The result was rawhide repo and I remove it:

[root@desk mythcat]# ls -l /etc/yum.repos.d/
[root@desk mythcat]# rm /etc/yum.repos.d/fedora-rawhide.repo 
[root@desk mythcat]# rm /etc/yum.repos.d/fedora-rawhide-modular.repo 

After that I reboot my distro and I used dnfdragora with my repos to test it.

Fedora 30 : DNF history.

This option of the tool DNF can help you to see and rollback by transaction history. NOTE: This option not work if you use the system-upgrade to another version of the distro.

[root@desk mythcat]# dnf
usage: dnf [options] COMMAND

List of Main Commands:

...
history                   display, or use, the transaction history
... 

This command displays DNF transaction history starting from the latest transaction on top of the listing.

[root@desk mythcat]# dnf history 
ID     | Command line             | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
    64 | groupupdate Minimal Inst | 2019-08-29 21:59 | Install        |    2   
    63 | groupupdate Minimal Inst | 2019-08-29 21:59 | Install        |    2   

To display information about this transaction use this command:

[root@desk mythcat]# dnf history info 64
Transaction ID : 64
Begin time     : Thu 29 Aug 2019 09:59:52 PM EEST
Begin rpmdb    : 1643:6a997d9fa53488ec0003727cb0394b18b6b4deaf
End time       : Thu 29 Aug 2019 09:59:53 PM EEST (1 seconds)
End rpmdb      : 1643:6a997d9fa53488ec0003727cb0394b18b6b4deaf
User           : Catalin George Festila 
Return-Code    : Success
Releasever     : 30
Command Line   : groupupdate Minimal Install
Packages Altered:
    Install @core                
    Install @minimal-environment 

To rollback the latest transaction use this:

[root@desk mythcat]# dnf history undo 64

Fedora 30 : Set up the Linux Malware Detect.

If you have an SELinux warning detection then the details you can see how can be fixed:

[mythcat@desk ~]$ su
Password: 
[root@desk mythcat]# ausearch -c 'systemd' --raw | audit2allow -M my-systemd
******************** IMPORTANT ***********************
To make this policy package active, execute:

semodule -i my-systemd.pp

[root@desk mythcat]# semodule -X 300 -i my-systemd.pp

This tool comes with three modes that the monitor can be executed with and they relate to what will be monitored.
These modes are USERS|PATHS|FILES.
The options break down as follows:

• USERS: The users option will take the homedirs of all system users that are above inotify_minuid and monitor them.If inotify_webdir is set then the users webdir, if it exists, will only be monitored;
• PATHS: A comma spaced list of paths to monitor;
• FILE: A line spaced file list of paths to monitor

$ maldet --monitor users
$ maldet --monitor /root/initial-setup-ks.cfg
$ maldet --monitor /home/mythcat

Let's test the USERS option:

[mythcat@desk maldetect-1.6.4]$ maldet --monitor users
Linux Malware Detect v1.6.4
            (C) 2002-2019, R-fx Networks 
            (C) 2019, Ryan MacDonald 
This program may be freely redistributed under the terms of the GNU GPL v2

maldet(7958): {mon} could not find inotifywait command, install yum package inotify-tools or 

download from https://github.com/rvoicilas/inotify-tools/wiki/


[root@desk maldetect-1.6.4]# dnf search inotify-tools
Last metadata expiration check: 0:01:39 ago on Wed 21 Aug 2019 11:09:22 PM EEST.
============================================ Name Exactly Matched: inotify-tools ======
inotify-tools.i686 : Command line utilities for inotify
inotify-tools.x86_64 : Command line utilities for inotify
================================================ Name Matched: inotify-tools ======
inotify-tools-devel.i686 : Headers and libraries for building apps that use libinotifytools
inotify-tools-devel.x86_64 : Headers and libraries for building apps that use libinotifytools
[root@desk maldetect-1.6.4]# dnf install inotify-tools.x86_64
...
Installed:
  inotify-tools-3.14-16.fc30.x86_64                                                                                          

Complete!
[root@desk maldetect-1.6.4]# maldet --monitor users
Linux Malware Detect v1.6.4
            (C) 2002-2019, R-fx Networks 
            (C) 2019, Ryan MacDonald 
This program may be freely redistributed under the terms of the GNU GPL v2

maldet(973): {mon} set inotify max_user_watches to 16384
maldet(973): {mon} added /dev/shm to inotify monitoring array
maldet(973): {mon} added /var/tmp to inotify monitoring array
maldet(973): {mon} added /tmp to inotify monitoring array
maldet(973): {mon} starting inotify process on 3 paths, this might take awhile...
maldet(973): {mon} inotify startup successful (pid: 1800)
maldet(973): {mon} inotify monitoring log: /usr/local/maldetect/logs/inotify_log

Fedora 30 : Testing the Linux Malware Detect.

Linux Malware Detect (LMD) is a malware scanner for Linux released under the GNU GPLv2 license, that is designed around the threats faced in shared hosted environments.
This tool is provided by R-fx Networks.
Let's install and test it:

[mythcat@desk ~]$ wget http://www.rfxn.com/downloads/maldetect-current.tar.gz
[mythcat@desk ~]$ tar -xf maldetect-current.tar.gz 
[mythcat@desk ~]$ cd maldetect-1.6.4/
[mythcat@desk maldetect-1.6.4]$ su
Password: 
[root@desk maldetect-1.6.4]# ./install.sh
Failed to enable unit: Unit file maldet.service does not exist.
Linux Malware Detect v1.6.4
            (C) 2002-2019, R-fx Networks <proj@r-fx.org>
            (C) 2019, Ryan MacDonald <ryan@r-fx.org>
This program may be freely redistributed under the terms of the GNU GPL

installation completed to /usr/local/maldetect
config file: /usr/local/maldetect/conf.maldet
exec file: /usr/local/maldetect/maldet
exec link: /usr/local/sbin/maldet
exec link: /usr/local/sbin/lmd
cron.daily: /etc/cron.daily/maldet
maldet(31046): {sigup} performing signature update check...
maldet(31046): {sigup} local signature set is version 201907043616
maldet(31046): {sigup} new signature set 2019081912001 available
maldet(31046): {sigup} downloading https://cdn.rfxn.com/downloads/maldet-sigpack.tgz
maldet(31046): {sigup} downloading https://cdn.rfxn.com/downloads/maldet-cleanv2.tgz
maldet(31046): {sigup} verified md5sum of maldet-sigpack.tgz
maldet(31046): {sigup} unpacked and installed maldet-sigpack.tgz
maldet(31046): {sigup} verified md5sum of maldet-clean.tgz
maldet(31046): {sigup} unpacked and installed maldet-clean.tgz
maldet(31046): {sigup} signature set update completed
maldet(31046): {sigup} 15552 signatures (12740 MD5 | 2035 HEX | 777 YARA | 0 USER)
[root@desk maldetect-1.6.4]# vim /usr/local/maldetect/conf.maldet

Change this row to scan_user_access=1
Now you can run it:

[mythcat@desk ~]$ /usr/local/sbin/maldet -a 
Linux Malware Detect v1.6.4
            (C) 2002-2019, R-fx Networks 
            (C) 2019, Ryan MacDonald 
This program may be freely redistributed under the terms of the GNU GPL v2

maldet(32628): {scan} signatures loaded: 15552 (12740 MD5 | 2035 HEX | 777 YARA | 0 USER)
maldet(32628): {scan} building file list for , this might take awhile...
maldet(32628): {scan} setting nice scheduler priorities for all operations: cpunice 19 , ionice 6
maldet(32628): {scan} file list completed in 13s, found 44109 files...
maldet(32628): {scan} scan of  (44109 files) in progress...