How to increase delay time for BIOS for VMWare Guest OS

To increase the BIOS delay time of your guest OS, open the folder containing your VMWare image (on Windows it should be on C:\Data\Virtual Machines\<YOUR_IMAGE_NAME).

Open with Notepad++ the file with extension .vmx  and modify or edit the setting

bios.bootDelay = "5000"

The delay is in milliseconds and the maximum value you can set is 10000 (10 seconds).


Alternatively if you put the line:
 
bios.forceSetupOnce = "FALSE"

You will get always the BIOS settings. So no crazy fast F2 typing required! This is useful for one-time changes (typically to change the boot sequence).


Another interesting link is this one, that explains how to increase the disk space on the guest os using gparted.


Source:
https://kb.vmware.com/

Restart ORACLE without using sqlplus

In Linux (as root):


To obtain help on the command:

/etc/init.d/oracle-xe help


Usage: ./oracle-xe {start|stop|restart|force-reload|configure|status|enable|disable}

To restart:

/etc/init.d/oracle-xe restart

Execute a script with sqlplus

To execute a sql-script with sqlplus just insert your this command:

(replace  : username, password, connection_string, /path/to/script)

echo exit | sqlplus username/password@connection_string@/path/to/script

Source:

http://serverfault.com/ 

How to check the exit code of a command (on Linux and Windows)

To check the exit code of an application on Linux and Windows is very easy.

In a Linux' bash, you need to issue the command: 

echo "$?"


echo "$?" will return the exit code of the previous command (please note that also an empty line counts as a command!)


In a Windows' command prompt:

echo %errorlevel%

Qt5 Hello World on CentOS from command line with gcc

Install the libraries (I assume you have already installed gcc 4.8.x & friends on your system):

The Qt5 (pronounced as cute-five) base components

sudo yum install qt5-qtbase* 

sudo yum install mesa-libGL-devel -y

Create your project's folder: 

>>mkdir hello_world_qt

>>cd hello_world_qt 

Write hello word C++ file:

>> vi hello_world_qt.cpp

with content: 

#include <QtWidgets/QApplication>
#include <QtWidgets/QPushButton>
 
int main(int argc, char **argv)
{
 QApplication app (argc, argv);
 
 QPushButton button ("Hello world !");
 button.show();
 
 return app.exec();
}

then make a qt project with qmake:

>>qmake-qt5 -project

edit the *new* file hello_world_qt.pro by adding the line QT += widgets before TEMPLATE. The final file will look similar to this:

######################################################################
# Automatically generated by qmake (3.0) Sun Feb 7 15:13:47 2016
######################################################################

QT += widgets

TEMPLATE = app
TARGET = hello2
INCLUDEPATH += .

# Input
SOURCES += hello_world_qt.cpp

Now generate the Makefile with qmake:

>>qmake-qt5 -makefile

Finally, you can compile your program:

>>make 

and run it!

>>./hello_world_qt

------------------------------------------------------- 

NOTE: I ended up with this solution because I got the errors below (missing libraries) 

/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:20: undefined reference to `QApplication::QApplication(int&, char**, int)'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:22: undefined reference to `QPushButton::QPushButton(QString const&, QWidget*)'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:23: undefined reference to `QWidget::show()'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:25: undefined reference to `QApplication::exec()'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:22: undefined reference to `QPushButton::~QPushButton()'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:25: undefined reference to `QApplication::~QApplication()'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:25: undefined reference to `QApplication::~QApplication()'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:22: undefined reference to `QPushButton::~QPushButton()'
/home/eddie/QT_HOME/hello_world_qt/hello_world_qt.cpp:22: undefined reference to `QPushButton::~QPushButton()'
collect2: error: ld returned 1 exit status 

Sources for this post:

https://csl.name/post/qt-gcc/

http://stackoverflow.com/