There are a thousand way - classic Linux way - through you can write in Hindi. But I will tell you about best and simplest.
The best way to write in Hindi in Linux in through online Hindi typing tool.
There were two most popular online Hindi typing tool that runs out of the box and does not need anything else - No preinstalled Java or anything else!
The first online Hindi typing tool is - Quillpad.
Quillpad's interface is clean and clutter free. You simply start typing in Roman Hindi in below pan and you get Hindi (Unicode) in its upper pan. It also suggest common Hindi words - a kind of spell check.
When you done typing, just copy paste this in your computer say on note pad or use in wordpress or in Blogger Blog tool - which now also has a nice Hindi Transliteration tool.
You simply type kya kar rahe hain aap? And you get - क्या कर रहे हैं आप?
So easy. Isn't it?
The other online Hindi typing tool is HindiKalam
Hindikalam has some not so intuitive interface, but it has an online demo Hindi Keyboard that helps you in typing Hindi correctly. It also gives you Hindi words as suggestion on the fly as you type. You type phonetic roman Hindi in left side and get Unicode Hindi in right pan. You can copy paste and save the data easily.
If you want to type Hindi on your Linux machine traditionally, ie in any Linux application then you need to install Hindi locale files, Hindi keyboard and Hindi fonts etc. In this case, it is advised to use Hindi-preconfigured Linux distribution such as BOSS OS. Use live BOSS Linux CD or install BOSS Linux in your computer and everything will be ready for you - simply select Language Hindi from system tray language icon and you are done.
If you are using other distribution, then you must follow instructions given here -
Tag hindi,linux,hindi blog,hindi linux