Linux

The su Command: Elevate Yourself

OS:  Unix / Linux

Often called the “Super User” command. The su (short for substitute user) command makes it possible to change a login session’s owner without the owner having to first log out of that session.

Although su can be used to change the ownership of a session to any user, it is most commonly used to change the ownership from an ordinary user to the root (i.e., administrative) user, thereby providing access to all parts of and all commands on the computer or system.

And like that of Goku from Dragon Ball Z you elevate yourself to be a powerful user.

Usage example:

sysadmin@jermsmit:~$ su
Password:
root@jermsmit:/home/sysadmin#

 

TunnelBear – Simple, Private and Free

TunnelBear has just launched a Chrome extension that helps to protect your privacy on a Chromebook, Android, iPhone, iPad, PC & Mac

TunnelBear is a Canadian company famous for making super easy to use privacy tools. They specialize in VPN services that allow your phone and computers to be secure when using public WiFi hotspots. Their service also allows you to “tunnel” into another country to get around content blocking by governments or media companies.

Today TunnelBear is launching a public beta version of their new Chrome extension. When installed, it will protect everything you do in Chrome by running it through an encrypted web proxy.

For Chromebook users, almost everything you do should be encrypted, making it a great tool to have. For Windows, Mac, or Linux users, please note that only your Chrome connection will be secured – not the rest of your system’s traffic.

TunnelBear offers a free plan for those with low data usage, or a very cheap paid plan for everyone else.

Credit for the original post: https://plus.google.com/+CraigTumblison  Thanks dude

Tech Short: Generate Pi to a given number in Linux

Its Pi day – Saturday, March 14 is Pi Day 2015

Why not do something cool in Linux like generate pi to a given number of decimal places.  This can be done by using the tool  bc (Bench Calculator) which is installed in most Linux distributions I have used.

The following command will calculate π to 10 decimal places

The results:  3.1415926532

So enjoy some pi

 

More and Resources Use –
scale=100 – this specifies the number of decimal places to use for the result
4*a(1) – this returns the arctangent of 1 [which equals 45°: 45 x (π/180), or ¼π] then multiplies by 4 to get π.
bc -l – pipe the complete function string into the bc utility, -l specifies to load the standard math library that’s needed for the arctangent function, a().

Info from: http://superuser.com/questions/275516/how-can-i-generate-pi-to-a-given-number-of-decimal-places-from-a-script

Retrieve MX records using nslookup

One of my new kids on the block asked me a question tonight; “Jermal, how do I get the mx record of a domain?”

To retrieve mx record information we need to use a tool called nslookup which is available in Windows and Linux

The quick syntax use is

 

Example of its usage

And what it looks like in

Linux

Windows

 

The mcrypt extension is missing. Please check your PHP configuration

After a quick LAMP install, I decided to install PhpMyAdmin. Logging into I noticed a warring message that read:

The mcrypt extension is missing. Please check your PHP configuration

To resolve this I attempted the following:

  • Elevated my console to root (sudo -i)
  • apt-get install mcrypt
  • apt-get install php5-mcrypt (no need because the previous command did it for me)
  • php5enmod mcrypt
  • service apache2 restart

If the above steps don’t work introduce the following: ln -s /etc/php5/conf.d/mcrypt.ini /etc/php5/mods-available

Now my LAMP install is complete.