opensuse lxde Leap 42.1

download from https://susestudio.com/u/kolaflash

cannot open display
==============
sudo -H env DISPLAY=:0 /part/to/command

autologin
======
sudo vi /etc/sysconfig/displaymanager
DISPLAYMANAGER_AUTOLOGIN="username"
DISPLAYMANAGER_PASSWORD_LESS_LOGIN="yes"

allow user to ping
=============
sudo chmod u+s `which ping`

Install CentOS 7 Via NetInstall

to create bootable USB key for installation
right click on Win32DiskImager and choose "Run as administrator"

NetInstall URL (Installation Source)
choose mirror from http://mirror-status.centos.org/
e.g.
http://mirror.centos.org/centos/7/os/x86_64/

Recommended Partitioning Scheme
/ = 5 GB for a minimal installation, at least 10 GB for a full installation
/boot/ = recommended size at least 500 MB
/boot/efi = should be at least 50 MB in size; its recommended size is 200 MB.
/var = at least 3 GB


https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Installation_Guide/sect-disk-partitioning-setup-x86.html#sect-recommended-partitioning-scheme-x86


Post install
=============
yum install -y gnome-terminal
gedit
libreoffice
firefox
ntfs-3g
gparted
shotwell
net-tools

yum -y install http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm
yum -y install vlc smplayer ffmpeg
yum -y install geeqie gthumb
http://wiki.centos.org/TipsAndTricks/MultimediaOnCentOS7



Samba
=====
https://www.howtoforge.com/samba-server-installation-and-configuration-on-centos-7

The smbpasswd command will be available after installing samba-client package.


antivirus
======
clamav
sudo freshclam


http://free.avg.com/us-en/download-free-all-product
sudo avgctl –start
sudo avgupdate
avgscan


command
========
yum clean all
yum search package_name
yum provides package_name
yum info package_name
sudo systemctl poweroff

Securing SSH on CentOS 7

vi  /etc/ssh/sshd_config


Port 23456
PermitRootLogin no
AllowUsers <<username>>
Protocol 2

service sshd restartyum install policycoreutils-python
semanage port -a -t ssh_port_t -p tcp 23456

Change the port number in
/usr/libfirewalld/services/ssh.xml
#Otherwise 'no route to host' error

firewall-cmd --reload

Client >> ssh -p 23456 serverip

More info http://wiki.centos.org/HowTos/Network/SecuringSSH

Auto-login LightDM to Cinnamon when Boot and Resume from Hibernate on Centos 7

I am setting my home file server and use its monitor to display cctv.


I don't want to enter password every time when boot and hibernate.
I want to only press the power button when turn on and off.

Here is how:

vi /etc/lightdm/lightdm.conf

[SeatDefaults]
autologin-user=<<username>>
autologin-user-timeout=0

Set the power button to hibernate the computer
vi /etc/systemd/logind.conf
HandlePowerKey=hibernate


To avoid login screen when resume from hibernate,
I disable lock screen.

gsettings set org.cinnamon.desktop.lockdown disable-lock-screen true

Install Cinnamon, LightDM to CentOS 7 Minimal Install

yum install -y epel-release
yum groupinstall "X Window System"
yum install -y cinnamon gnome-icon-theme-legacy.noarch
yum groupinstall Fonts

(execute this command as a ordinary user / not as root)
echo "exec /usr/bin/cinnamon-session" >> ~/.xinitrc

yum install -y lightdm
systemctl set-default graphical.target# rm '/etc/systemd/system/default.target'
# ln -s '/usr/lib/systemd/system/graphical.target' '/etc/systemd/system/default.target'
# systemctl enable lightdm.service
# startx

When resume from hibernate, all open applications always gone.
If I switched to text mode by pressing Ctrl+Alt+F2
then pm-hibernate or systemctl hibernate,
the applications will still alive.

So Here is how I fix it:

vi /etc/systemd/system/display-manager.service
[Service]
;Restart=always


Thanks
http://centoshowtos.org/desktop/cinnamon-on-centos-7/
http://unix.stackexchange.com/questions/181503/how-to-install-desktop-environments-on-centos-7
http://jensd.be/?p=125

How to Install VirtualBox 4.3 on CentOS 7

Here is my note how I successfully install and run VirtualBox 4.3 on CentOS 7


yum install epel-release
yum install dkms kernel-headers kernel-devel


vi /etc/yum.repos.d/virtualbox.repo

[virtualbox]
name=Oracle Linux / RHEL / CentOS-$releasever / $basearch - VirtualBox
baseurl=http://download.virtualbox.org/virtualbox/rpm/el/$releasever/$basearch
enabled=1
gpgcheck=1
gpgkey=http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc

# export KERN_DIR=/usr/src/kernels/2.6.32-504.3.3.el6.x86_64 

yum install VirtualBox-4.3
usermod -a -G vboxusers username

To handle "Can’t create temporary cache file /etc/ld.so.cache~: Permission denied" :
setenforce Permissive
service vboxdrv setup
setenforce Enforcing

thank : 
http://tecadmin.net/install-oracle-virtualbox-on-centos-redhat-and-fedora/
http://www.itzgeek.com/how-tos/linux/centos-how-tos/install-virtualbox-4-3-on-centos-7-rhel-7.html