Unfortunately, NP++ is not available for Linux. Sure you can get it working via WINE, but I'd rather have something that provides similar features that just works in Linux. Notepad++ uses Scintilla as it's core editing component.
Luckily, there are several IDEs for Linux that use Scintilla, so the features and feel of Notepad++ are not lost to the Linux world.
Geany is the editor that I've been using lately (along with vi/vim). Currently at version 0.18, Geany has a long list of features and supports many of the common scripting and programming languages. One of the primary goals of the development was to limit dependencies, thus Geany only requires the GTK2 runtime libraries and is agnostic to the desktop (Gnome, KDE, etc...).
Here are some of the features listed on the website:
- Syntax highlighting
- Code folding
- Symbol name auto-completion
- Construct completion/snippets
- Auto-closing of XML and HTML tags
- Call tips
- Many supported filetypes including C, Java, PHP, HTML, Python, Perl, Pascal (full list)
- Symbol lists
- Code navigation
- Build system to compile and execute your code
- Simple project management
- Plugin interface (see Plugins)
If you are running Fedora, Geany and various plugins can be installed using the following Yum command:
$ sudo yum install geany geany-plugins-*
If you'd like to stick to Gedit, you can pimp it out using this guide. The advantage here, Gedit is available on most distributions right out of the box (assuming a graphical install).