Newbie’s to Linux often face the dilemma of where to install or put the binaries of any software app they wish to run on their Linux. If that app comes with a installer it’s ok but if not then It’s tough time , well here I would recommend some important points to consider  while choosing the directories for installation of your Apps etc.

If you are using some package manager like Synaptic (Ubuntu) , YUm or apt-get then the locations are automatically chosen for you and are in most case /bin or /usr/bin for the executables .

If you are installing LAMP then install it to /opt or /etc directory and while you can keep the WEB ROOT at /var/www or in some other Linux’s at /srv/www

As I told you, Apps tend to be installed in /usr/bin, /usr/local/bin, or in some cases /opt. If you’re developing your own software or modifying an existing package /usr/local/bin is probably better as it signifies a user edited binary file

To Learn more about significance and usage of filesystem hierarchy of Linux , Download this PDF from pathname.com , or read it  Online ( HTML) version here

Pictorial representation of Linux FileSystem

Here are two images, I found on the internet which explain the various Directories under Linux file system in brief within a small single page image.

(Click on image to Expand it )

Here is another one much colorful and Web2

Hope this helped you understand to some extent , meaning and importance of various directories under Linux root filesystem.

(Image credit goes to the creator, If you are the one just notify me in comments and I will update it here in Post )