Linux: Find Out Directory Size Command

I am a new Linux user. How do I find out size of a directory on Linux operating systems using command line options?   You need to use the du command: [a] Find and estimate…

Debian / Ubuntu: apt-get Force Reinstall Package

I am a new Debian Linux v.7.x / Ubuntu Linux LTS user. How do I reinstall a package using apt-get command line?   The Advanced Packaging Tool (APT) works on both Debian / Ubuntu and…

HowTo: OS X Take a Screenshot On My Mac Desktop

I can use Shutter app in GNU/Linux to take a screenshot of a specific area, window, whole screen, or even of a website. How do I take a screenshot on my mac book pro/mini desktop…

Linux: Find Out What Is Using TCP Port 80

H ow do I find out what is listing or using tcp port number 80 on Linux based systems using command line options?   You can use any one of the following command to find…

Fedora Linux: Restart / Stop / Start DHCPD Server Command

I am a new Fedora Linux version 18 system administrator. How do I restart dhcpd server using command line options in Fedora Linux server running on HP server hardware?   DHCP (Dynamic Host Configuration Protocol)…

HowTo: Pronounce Mac OS X

I am a new Apple Mac book pro user. Is Mac OS X pronounced as “Mac OS E-X” or “Mac OS Ten”? How do you pronounce the Apple Mac os X? How do I find…

Linux / Unix: Sort ls Command Output By Last Modified Date and Time

I download lots of files in ~/Downloads/ folder in Ubuntu Linux and OS X desktop. How do I show last downloaded file first using the ls command? How do I sort the output of ls…

How To Find a Directory On Linux Based System

I just switched from MS-Windows server admin to Debian Linux server admin role. I need to find a directory called project.images. I was also told that the locate command is the simplest and quickest way…

Mac OS X: Set / Change $PATH Variable

I need to add dev tools (such as JDK and friends) to my PATH. How do I change $PATH variable in OS X 10.8.x? Where does $PATH get set in OS X 10.8 Mountain Lion?…

Ubuntu Linux LTS: Force Kernel Package Updates Which Have Been Kept Back

I am using Ubuntu 12.04.2 LTS (“precise”). I am trying to upgrade all packages using kernel via apt-get upgrade method. But, I am getting the following message: apt-get upgrade Reading package lists… Done Building dependency…