What I'm looking for is the Notepad++ feature where I can highlight words on right clicking and choosing one of the 5 styles (so that all instances of that word get highlighted with that color), in some editor in linux (Red hat). I find that it helps me in understanding new code.
Emacs can do it. Once you've loaded a file, press:
Alt + s then h and finally r
or alternatively if your version of Emacs doesn't recognize the previous shortcut:
Alt + x then type
highlight-regexp and press Enter
Emacs will ask you the regexp (a simple word or phrase will work too) to highlight, then it will ask you the color name too, usually starting with
hi-yellow (you can use Tab to complete). That's all.
It may sound complicated but that's Emacs; there are plenty of ways to speed up this process if you want to mess up with it. And I suggest you to do so.
I believe you can use jEdit and the highlight plugin to achieve what you are looking for...
Highlight: Highlights words (or matched regexps) with different colors.
Use Geany. It is the best native linux alternative for Notepad++:
Geany is a text editor using the GTK2 toolkit with basic features of an integrated development environment. It was developed to provide a small and fast IDE, which has only a few dependencies from other packages. It supports many filetypes and has some nice features.