Tue 21 Jul 2020 05:02:14 PM UTC

Why can't I unlock from the KDE's screen locking program?

Because KDE's screen locking program needs to read the password in the user domain while all user domains are not allowed to read password by the security policy. Please turn off KDE's screen locking program and run XScreenSaver instead.
The XScreenSaver is available for KDE.

Sun Sep  1 07:05:43 UTC 2019

Note when upgrading to Xfce 4.14!
See Xfce 4.14 and XScreenSaver 5.43

Wed Feb 13 07:21:13 UTC 2019

Why when I download omarine-6.1-dvd.iso, there is a login dialog with username and password?

Because at that time there were too many clients downloading simultaneously. Our server limits MaxClients to 30 by default. We will increase this value at the appropriate time (when the server is idle).

Mon Feb 4 02:26:30 UTC 2019

How to run wireshark properly?

In order to use wireshark, you need to ensure the following:

1) Add the user to the wireshark group, as the root user

usermod -a -G wireshark <username>

2) The SELinux user is staff_u

3) Turn on the condition allow_wireshark, as the root user

setsebool -P allow_wireshark on

(Suppose you have updated the policy using omarine-update, otherwise switch to permissive mode, as the root user: setenforce 0)

4) Optional. Stop your firewall, eg (as the root user)

systemctl stop firewall@wlp

Fri Dec 21 03:54:33 UTC 2018

How to know available disk space using command line?

For example the root partition, to know the disk space usage you run this command:

df -h /

Tue Dec 18 01:34:37 UTC 2018

Advanced Query: How to find packages that depend on a given library?

For example library, you run this command to find all packages in the system which depend on

for pkg in $(rpm -qa); do
if rpm -qR $pkg | grep -q libsasl; then
echo $pkg

Thu Nov 15 03:14:12 UTC 2018

How to switch to permissive mode permanently?

Not recommended! However, if you want to switch to permissive mode permanently for development purposes, you can modify the /etc/selinux/config configuration file by running the following command, as the root user:

sed -i '/^SELINUX=/c SELINUX=permissive' /etc/selinux/config

What package manager does Omarine come with? I executed # yum update but yum : command not found is the output.

The package manager is RPM. Did you mean an automatic update program? We plan to build Omarine Update 3.0, similar to the Omarine Update we have built for Omarine 2.0 before.

Wed Nov 14 05:29:30 UTC 2018

My system has problems after upgrading some packages!

In SELinux, these problems is usually caused by the file system being mislabeled. You create file /.autorelabel and reboot.

Note: If you can not login through the graphical login screen, you can still switch to another virtual console by simultaneously pressing keys Ctrl-Alt-Fn (n = 1, 2, 3, ...). If you still can not boot, specify enforcing=0 on the kernel command line.

Wed Sep 5 02:11:53 UTC 2018

What are the Login credentials? Name and Password?

The name is for the system to identify a valid account that the system has provided with certain access rights to the resource. Password used to authenticate the account. However, the password is only one of the login credentials. It is not as good as other methods and needs to be encrypted when going over the network. An example of secure login is to use ssh with the cryptographic keys. See for more details.

Mon Sep 3 09:19:58 UTC 2018

I am using Omarine 4.0. Can I upgrade to Omarine 4.1?

Yes, if you install enough packages as indicated in Omarine-log, your system becomes Omarine 4.1.

Thu Aug 23 07:06:58 UTC 2018

What torrent client do I use?

You use qBittorrent.

Wed Jun 13 23:06:48 UTC 2018

Note the filename containing the spaces!

When using filenames (or directories) containing spaces on the command line, you need to enclose them in quotes. For example:

clamdscan "/path/to/name of directory"

Sun Jun 10 04:06:21 UTC 2018

How to install additional fonts?

See this article.

Sat Jun 9 09:27:38 UTC 2018

Can I manipulate Microsoft Office documents such as .docx, .xlsx, .pptx?

Yes, of course. You copy them to your home directory and then open them.

Mon May 21 04:30:38 UTC 2018

How to take photos and videos using a webcam?

You run Cheese program.

Sat May 19 23:12:35 UTC 2018

Why do not I see k3b when querying with rpm?

Because k3b and some other application packages that belong to the kde category are included in one package. It's kde-apps package.

Sat May 19 13:34:50 UTC 2018

Notice the addition of Thunderbird!

When packing omarine-3.1-dvd.iso I have to remove some packages so that the size of omarine-3.1-dvd.iso is smaller than 4.7GB (not GiB), from which users can burn it to a regular DVD. These packages include Thunderbird. So, after installing Omarine 3.1 from omarine-3.1-dvd.iso, if you want to use Thunderbird and other packages below, download and install them:

Fri May 18 09:01:42 UTC 2018

I started ktorrent on GNOME and it disappeared. Where is it?

The program window is minimized to the lower left corner of the screen:

Fri May 18 06:01:34 UTC 2018

How to customize maximum number of directories to be protected by Clam AntiVirus?

See How to set number of directories to be protected by Clam AntiVirus?.

Thu May 17 18:31:32 UTC 2018

How to use Clam AntiVirus program?

First you run the following command to initialize the virus database:

sudo freshclam

Then start the clamav-daemon service:

sudo systemctl enable clamav-daemon
sudo systemctl start clamav-daemon

To protect your Downloads directory with on-access prevention, run the following command:

sudo tee -a /etc/clamd.conf << EOF
ScanOnAccess yes
OnAccessIncludePath $HOME/Downloads
OnAccessPrevention yes
OnAccessMaxFileSize 100M

Then restart the clamav-daemon service:

sudo systemctl restart clamav-daemon

See clamd.conf(5) for more details.

To schedule a virus scan of your home directory automatically at 3 AM every day you run this command:

echo "1 3 * * *       /usr/bin/clamdscan /home" \
| sudo tee -a /var/spool/cron/crontabs/root

If you want to scan files and directories manually, you can use clamscan or clamdscan. For example, scanning the Downloads directory with the archive recursion level limit set to 20:

clamscan --max-recursion=20 ~/Downloads

See clamscan(1) and clamdscan(1) for more details.

Log files are located in /var/log/clamav.

Thu May 17 04:09:40 UTC 2018

Notice when upgrading to XScreenSaver 5.39

If you are using XScreenSaver, after upgrading you need to restore xscreensaver.desktop:

sudo cp /usr/share/xscreensaver/xscreensaver.desktop /etc/xdg/autostart/

Mon Apr 30 13:50:50 UTC 2018

My computer has only one network interface that is Ethernet interface and I can not connect to the Internet!

You try disabling ipstatic service:

sudo systemctl disable ipstatic

Then restart your computer.

Fri Mar 30 14:01:23 UTC 2018

Fixing multipathd service:

The multipathd service is known to fail. We fix as follows:

sudo tee /etc/multipath.conf << EOF
defaults {
multipath_dir "/lib"
sudo sed 's,scsi_dh_alua scsi_dh_emc scsi_dh_rdac\s,,' -i /lib/systemd/system/multipathd.service
sudo mkdir -p /etc/multipath/
sudo dracut --force -o multipath

Fri Mar 30 03:00:02 UTC 2018

Resolving Dracut error message:
dracut-install: ERROR: installing '/etc/idmapd.conf'
If this message appears when running dracut, it is because your system has not configured NFSv4 and does not yet have the /etc/idmapd.conf file. The immediate solution is to add this file:

sudo touch /etc/idmapd.conf

Thu Mar 29 07:25:40 UTC 2018

How to generate and use an initramfs/initrd image?

sudo dracut &&
sudo grub-mkconfig -o /boot/grub/grub.cfg

See Dracut man page for details.

Mon Mar 26 03:30:40 UTC 2018

How to take screenshots in Plasma?

You run KScreenGenie: Applications > Utilities

Sun Mar 25 06:15:07 UTC 2018

How to capture the screen right at the login screen?

The user at the login screen is gdm. This user has the home directory at /var/lib/gdm.
You take screenshots as usual (press PrtSc key). The image files will be saved in /var/lib/gdm.

Sat Mar 24 06:38:09 UTC 2018

How to configure static IP?
The configuration file is /etc/sysconfig/ipstatic. It looks like this:

You modify the file then restart the computer.

Install JRE CA-Certificates (JRE Certificate Authority Certificates)

sudo rm -f /opt/jdk/jre/lib/security/cacerts &&
sudo makeca -f &&
sudo makeca-java

The above commands will generate keystore /opt/jdk/jre/lib/security/cacerts.
The default password used to protect the integrity of the keystore is "changeit". To change the password you run this command:

sudo keytool -storepasswd -keystore /opt/jdk/jre/lib/security/cacerts

Once changed the password, you need to modify the makeca-java script for the next update:

sudo sed -e '/declare\s-i/i read -s -p "Enter keystore password: " storepassword\n' \
-e 's,changeit,$storepassword,' -i /usr/sbin/makeca-java

Have fun!

Fri Mar 23 09:45:34 UTC 2018


1) XScreenSaver has a smart animation and i like it:

First of all you need to turn off screen blanking and screen locking of GNOME and Plasma.

GNOME: All Settings > Power

- System Settings > Desktop Behavior > Screen Locking

- System Settings > Power Management > Activity Settings

Then run Screensaver program.


Plasma: Applications > Settings

2) I don't use XScreenSaver:

Well, you can turn off XScreenSaver.

Remove xscreensaver.desktop:

sudo rm /etc/xdg/autostart/xscreensaver.desktop

Remove .xscreensaver:

rm -f ~/.xscreensaver

Reboot your machine.

How to use the internationalization input method?
See Using the input method.

Wed Mar 21 05:17:55 UTC 2018

How to check SHA256 digest?

echo "c2f012673bb0c41fda36c3d8776ddcb598a824adf0300bfb9f03fee7abbb2325 omarine-3.0-dvd.iso" | sha256sum -c

Setup Canon LBP printer driver, for example LBP2900:

sudo captprinter-setup LBP2900

Upgrade (or install, query) package files directly from the internet, for example makeca-1.0.2-1.x86_64.rpm:

sudo rpm -U