How to fix ... System program problem detected Do you want to report the problem now? (Ubuntu)

This popup comes from apport.  It is a process that will collect and report and problem.  From Ubuntu wiki:

Apport is a system which

•     intercepts crashes right when they happen the first time,
•     gathers potentially useful information about the crash and the OS environment,
•     can be automatically invoked for unhandled exceptions in other programming languages (e. g. in Ubuntu this is done for Python),
•     can be automatically invoked for other problems that can be automatically detected (e. g. Ubuntu automatically detects and reports package installation/upgrade failures from update-manager),
•     presents a UI that informs the user about the crash and instructs them on how to proceed,
•     and is able to file non-crash bug reports about software, so that developers still get information about package versions, OS version etc. 

edit /etc/default/apport
Change enabled=1
to enabled=0

Then

sudo  /etc/init.d/apport restart

How to set Ubuntu vmware guest screen resolution to 1920 x 1080

xrandr --newmode "1920x1080"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync
xrandr --addmode Virtual1 1920x1080
xrandr --output Virtual1 --mode 1920x1080

How to copy fonts from Windows to Ubuntu

To make new fonts available system-wide on ubuntu, copy fonts into /usr/share/fonts using nautilus.

Nautilus has to be rooted.  Launch with:
gksu nautilus

We can create subdirectory to organize font files.

The system will automatically convert font to ubuntu format.

Next, clear the font cache with this command

sudo fc-cache -v -f

Done.

How to control (start/stop/enable/disable) services using systemd in linux

This applies to system using systemd to control service such as Fedora, Ubuntu 15.04, Centos, Debian (later version)

systemctl     - > list all services
systemctl status mysqld   -> check mysqld service status
systemctl {start|stop|restart|enable|disable} mysqld    -> perform service control

systemctl mask mysqld    -> mysqld cannot be started even manually.  Have to unmask

systemctl is-enabled mysqld   -> check if mysqld is enabled


systemctl isolate {multi-user.target|runlevel3.target}   -> switch to run level 3
systemctl isolate {graphical.target|runlevel5.target}    -> switch to run level 5

systemctl set-default <name of target>.target    -> set default target
systemctl get-default                                           -> get current target

systemctl list-units --type=target      ->   list of all possible targets

For further info
man systemd
or https://fedoraproject.org/wiki/Systemd

How to activate networking after install centos 7 minimally

use nmcli & nmtui

nmcli         ; check the current networking device setting

nmtui         ; a text ui to configure network. use edit and check auto start networking, exit , done

How to type a special character?

To enter these, you follow the standard Unicode entry sequence:
Control + Shift + U, unicode hex (in lower case), Return

To find out the Unicode of a character, can use this web site.

http://www.babelstone.co.uk/Unicode/whatisit.html

Check if and how swap file is used

free -m

Check if and how swap is used