Tuesday, August 25, 2020

Fedora 32 : Change display manager.

The display manager is a graphical login manager which starts a session, simply asks username and password to login desktop.
On Fedora, you can choose for example GDM (Gnome Display Manager), SDDM (Simple Desktop Display Manager), LXDM (LXDE Display Manager), LightDM, KDM (KDE Display Manager), XDM (X Display Manager).
I like the old gdm display manager, is good and works great.
If you want to change it then use these commands:
[root@desk mythcat]# dnf install gdm
[root@desk mythcat]# systemctl disable lightdm 
[root@desk mythcat]# systemctl enable gdm
Failed to enable unit: File /etc/systemd/system/display-manager.service already exists and is a symlink to /usr/lib/systemd/system/sddm.service.
[root@desk mythcat]# systemctl disable sddm.service 
Removed /etc/systemd/system/display-manager.service.
[root@desk mythcat]# systemctl enable gdm
Created symlink /etc/systemd/system/display-manager.service → /usr/lib/systemd/system/gdm.service.
[root@desk mythcat]# reboot
If you have problems with gdm display manager then you can read about settings here.
The configuration file can be found in this file:
[root@desk mythcat]# cat /etc/gdm/custom.conf 
# GDM configuration storage

# Uncomment the line below to force the login screen to use Xorg



# Uncomment the line below to turn on debugging

Sunday, August 23, 2020

Fedora 32 : Install LibreOffice_7.0.0 .

The latest releases of LibreOffice is version 7.0.0 and is available for Fedora 32 distro from here. To install it you need to use these commands:
[root@desk mythcat]# dnf -y update
[mythcat@desk ~]$ cp Downloads/LibreOffice_7.0.0_Linux_x86-64_rpm.tar.gz ~
[mythcat@desk ~]$ ls LibreOffice*
[mythcat@desk ~]$ tar xvf LibreOffice_7.0.0_Linux_x86-64_rpm.tar.gz 
[mythcat@desk ~]$ cd LibreOffice_7.0.0.3_Linux_x86-64_rpm/
[mythcat@desk LibreOffice_7.0.0.3_Linux_x86-64_rpm]$ cd RPMS/
[mythcat@desk RPMS]$ sudo dnf install *.rpm
[sudo] password for mythcat: 
Last metadata expiration check: 2:09:12 ago on Sat 22 Aug 2020 10:33:11 PM EEST.
Dependencies resolved.
 Package                                    Arch   Version   Repository    Size
 libobasis7.0-base                          x86_64 @commandline 1.8 M
 libobasis7.0-calc                          x86_64 @commandline 9.5 M
 libobasis7.0-core                          x86_64 @commandline 101 M
 libobasis7.0-draw                          x86_64 @commandline 6.1 k
 libobasis7.0-en-US                         x86_64 @commandline  88 k
The last step is to run this software from Fedora 32 distro desktop environment.

Tuesday, August 18, 2020

Fedora 32 : Repair the starting LightDM display manager.

LightDM is a cross-desktop display manager with these features:
  • Cross-desktop - supports different desktop technologies.
  • Supports different display technologies (X, Mir, Wayland ...).
  • Lightweight - low memory usage and high performance.
  • Supports guest sessions.
  • Supports remote login (incoming - XDMCP, VNC, outgoing - XDMCP, pluggable).
  • Comprehensive test suite. 
  • Low code complexity.
To start it you need to use these commands:
[mythcat@desk ~]$ sudo systemctl get-default
[sudo] password for mythcat: 
[mythcat@desk ~]$ sudo systemctl set-default graphical.target
Removed /etc/systemd/system/default.target.
Created symlink /etc/systemd/system/default.target → /usr/lib/systemd/system/graphical.target.
Restart your Fedora distro and use it.

Saturday, August 15, 2020

Fedora 32 : Accurate timekeeping with chronyd daemon.

Accurate timekeeping is important in networking because accurate time stamps in packets and logs are required.
In Linux operating systems, the NTP protocol is implemented by a daemon running in userspace.
For Fedora distro, you can choose between the daemons ntpd and chronyd. Today I will show you how to use the chronyd.
The Fedora documentation can be found on the official website.
Let's install and use this:
[root@desk mythcat]# dnf install chrony 
[root@desk mythcat]# vim /etc/chrony.conf 
With the vim tool now you can add the In most cases, it's best to use pool.ntp.org to find an NTP server or use servers from your country. Now, I can start and enable the daemons named chronyd and add it to the firewall.
[root@desk mythcat]# systemctl start chronyd 
[root@desk mythcat]# systemctl status chronyd 
● chronyd.service - NTP client/server
     Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; vendor p>
     Active: active (running) since Sat 2020-08-15 12:23:08 EEST; 9h ago
       Docs: man:chronyd(8)
   Main PID: 10071 (chronyd)
      Tasks: 1 (limit: 11800)
     Memory: 1.0M
        CPU: 93ms
     CGroup: /system.slice/chronyd.service
             └─10071 /usr/sbin/chronyd

Aug 15 12:23:08 desk systemd[1]: Starting NTP client/server...
Aug 15 12:23:08 desk chronyd[10071]: chronyd version 3.5 starting (+CMDMON +NTP>
Aug 15 12:23:08 desk chronyd[10071]: Frequency -13.819 +/- 0.344 ppm read from >
Aug 15 12:23:08 desk chronyd[10071]: Using right/UTC timezone to obtain leap se>
Aug 15 12:23:08 desk systemd[1]: Started NTP client/server.
Aug 15 12:23:13 desk chronyd[10071]: Selected source
Aug 15 12:23:13 desk chronyd[10071]: System clock TAI offset set to 37 seconds

[root@desk mythcat]# systemctl enable chronyd 
[root@desk mythcat]# firewall-cmd --add-service=ntp --permanent 
[root@desk mythcat]# firewall-cmd --reload 
You can use it with chronyc command tool:
[root@desk mythcat]# chronyc sources 
210 Number of sources = 4
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
^+ blackmamba-g0.eff.ro          3  10   377   692  -1192us[-1273us] +/-   92ms
^+ corporate1.bluepink.ro        2  10   377   200  -1441us[-1441us] +/-   52ms
^+ static-5-2-155-141.rdsne>     2  10   377   468  +1622us[+1540us] +/-   51ms
^* dummy.upcnet.ro               2  10   377   435  -1221us[-1303us] +/-   57ms
[root@desk mythcat]# chronyc tracking
Reference ID    : 4E600719 (dummy.upcnet.ro)
Stratum         : 3
Ref time (UTC)  : Sat Aug 15 19:06:18 2020
System time     : 0.000439648 seconds fast of NTP time
Last offset     : -0.000081712 seconds
RMS offset      : 0.000591977 seconds
Frequency       : 13.753 ppm slow
Residual freq   : -0.000 ppm
Skew            : 0.235 ppm
Root delay      : 0.069966756 seconds
Root dispersion : 0.017129980 seconds
Update interval : 1036.2 seconds
Leap status     : Normal
[root@desk mythcat]# chronyc activity
200 OK
4 sources online
0 sources offline
0 sources doing burst (return to online)
0 sources doing burst (return to offline)
0 sources with unknown address 

Friday, August 7, 2020

Fedora 32 : First example with C# on Fedora distro.

Let's enable the COPR repository for dotnet:
[mythcat@desk ~]$ sudo dnf copr enable @dotnet-sig/dotnet
[sudo] password for mythcat: 
Enabling a Copr repository. Please note that this repository is not part
of the main distribution, and quality may vary.

The Fedora Project does not exercise any power over the contents of
this repository beyond the rules outlined in the Copr FAQ at
and packages are not held to any quality or security level.

Please do not file bug reports about these packages in Fedora
Bugzilla. In case of problems, contact the owner of this repository.

Do you really want to enable copr.fedorainfracloud.org/@dotnet-sig/dotnet? [y/N]: y
Repository successfully enabled.
Install the .NET Core package:
[mythcat@desk ~]$ sudo dnf install dotnet
Copr repo for dotnet owned by @dotnet-sig         42 kB/s |  59 kB     00:01    
Dependencies resolved.
 Package                           Arch      Version            Repository  Size
 dotnet                            x86_64    3.1.106-1.fc32     updates     11 k
Installing dependencies:
 aspnetcore-runtime-3.1            x86_64    3.1.6-1.fc32       updates    6.2 M
 aspnetcore-targeting-pack-3.1     x86_64    3.1.6-1.fc32       updates    945 k
 dotnet-apphost-pack-3.1           x86_64    3.1.6-1.fc32       updates     70 k
 dotnet-host                       x86_64    3.1.6-1.fc32       updates    104 k
 dotnet-hostfxr-3.1                x86_64    3.1.6-1.fc32       updates    164 k
 dotnet-runtime-3.1                x86_64    3.1.6-1.fc32       updates     27 M
 dotnet-sdk-3.1                    x86_64    3.1.106-1.fc32     updates     41 M
 dotnet-targeting-pack-3.1         x86_64    3.1.6-1.fc32       updates    1.8 M
 dotnet-templates-3.1              x86_64    3.1.106-1.fc32     updates    1.8 M
 netstandard-targeting-pack-2.1    x86_64    3.1.106-1.fc32     updates    1.3 M

Transaction Summary
Install  11 Packages

Total download size: 79 M
Installed size: 298 M
Is this ok [y/N]: 
Use this tutorial to install Visual Studio Code. Press Ctr-P keys to install the C# extension by OmniSharp.
ext install ms-dotnettools.csharp
The last step is to create a application HelloWorld:
[mythcat@desk ~]$ dotnet new console -o HelloWorld

Welcome to .NET Core 3.1!
SDK Version: 3.1.106

Explore documentation: https://aka.ms/dotnet-docs
Report issues and find source on GitHub: https://github.com/dotnet/core
Find out what's new: https://aka.ms/dotnet-whats-new
Learn about the installed HTTPS developer cert: https://aka.ms/aspnet-core-https
Use 'dotnet --help' to see available commands or visit: https://aka.ms/dotnet-cli-docs
Write your first app: https://aka.ms/first-net-core-app
Getting ready...
The template "Console Application" was created successfully.

Processing post-creation actions...
Running 'dotnet restore' on HelloWorld/HelloWorld.csproj...
  Restore completed in 119.48 ms for /home/mythcat/HelloWorld/HelloWorld.csproj.

Restore succeeded.
You can run it with dotnet run command:
[mythcat@desk ~]$ cd HelloWorld/
[mythcat@desk HelloWorld]$ ls
HelloWorld.csproj  obj  Program.cs
[mythcat@desk HelloWorld]$ dotnet run Program.cs 
Hello World!

Sunday, August 2, 2020

Fedora 32 : Play games with Steam service.

Steam is a video game digital distribution service by Valve. It was launched as a standalone software client in September 2003 as a way for Valve to provide automatic updates for their games, and expanded to include games from third-party publishers., see Wikipedia.
Is very easy to install and play a game with Fedora 32 Linux distro, just follow these commands:
[mythcat@desk ~]$ sudo dnf update --refresh
[sudo] password for mythcat: 
Fedora 32 openh264 (From Cisco) - x86_64        1.1 kB/s | 986  B     00:00    
Fedora Modular 32 - x86_64                       39 kB/s |  22 kB     00:00    
Fedora Modular 32 - x86_64 - Updates             26 kB/s |  22 kB     00:00    
Fedora 32 - x86_64 - Updates                     10 kB/s | 9.8 kB     00:00    
Fedora 32 - x86_64                               20 kB/s |  23 kB     00:01    
google-chrome                                   7.6 kB/s | 1.3 kB     00:00    
MEGAsync                                        4.7 kB/s | 1.5 kB     00:00    
MongoDB Repository                              4.4 kB/s | 2.5 kB     00:00    
RPM Fusion for Fedora 32 - Free - Updates        21 kB/s | 9.1 kB     00:00    
RPM Fusion for Fedora 32 - Free                  25 kB/s |  10 kB     00:00    
RPM Fusion for Fedora 32 - Nonfree - Updates     20 kB/s | 9.3 kB     00:00    
RPM Fusion for Fedora 32 - Nonfree               18 kB/s |  10 kB     00:00    
Visual Studio Code                              6.6 kB/s | 3.0 kB     00:00    
Dependencies resolved.
Nothing to do.
[mythcat@desk ~]$ sudo dnf install steam -y
Last metadata expiration check: 0:00:09 ago on Sun 02 Aug 2020 04:59:49 PM EEST.
Package steam- is already installed.
Dependencies resolved.
Nothing to do.
[mythcat@desk ~]$ steam 
Running Steam on fedora 32 64-bit
STEAM_RUNTIME is enabled automatically
Pins potentially out-of-date, rebuilding...
Now you can pick a game from store steam and play it.