Best Shell IDE
There is no shell scripting ide. There are some examples of text editors that help you to write code.
1. Sublime Text
Sublime Text has many powerful features that make coding painless. It has all basic features mentioned on this page and many others like multi-select (hold CTRL and put mouse cursor in another line), creating your own snippets(lines of code that repeat), minimap(zoomed view of entire file).
2. Atom
Atom is developed by Github so it supports Github integration. It is often called the “hackable IDE of 21st century”, so you could easy customize almost everything.
Cool visual extension is “Power mode”, every time you hit a key, editor does a little move, like you hit the screen.
3. Geany
Geany is a lightweight IDE, aims to provide fast development environment. Features: filebrowser, save actions( autosave, instantsave, backupcopy), split window. In ubuntu you can install Geany using apt:
sudo apt-get install geany
4. Kate
It is a pre-installed text editor in Kubuntu. Some of the useful features: embedded terminal, SQL plugin, find and replace, syntax highlighting, bracket matching, auto backup, auto-completion with argument handling.