Are there any well known and well used shell scripting IDEs for Un*x?

Are there any IDEs targeted at shell scripting, specifically bash and zsh scripts? This means having syntax-highlighting for shell scripts and more importantly debugging environments with features like breakpoints, variable inspection and modification, etc., just like those available for regular programming languages like Python, Java, and C. For instance Microsft Windows [Powershell](http://en.wikipedia.org/wiki/Windows_PowerShell) has IDEs like [Powershell Plus](http://www.idera.com/productssolutions/freetools/powershellplus) and [PowerGui](http://www.powergui.org) . Googling brought up a combination of [ShellEd](http://sourceforge.net/projects/shelled/) , an Eclipse plugin for editing shell scripts, and [BashEclipse](http://sourceforge.net/projects/basheclipse/) , a Bash debugger that works with ShellEd; I haven't tried it yet. Are there any other shell scripting IDEs for Un*x similar to this combo? Does anyone have some experience with them?