Is there a need for Shell script debugger?

[srini]

    I am interested in finding out from those extensive shell programmers
    and others if there is a need for a debugger, like dbx, sdb, adb etc.
    for shell procedures. 
    If you think there is a need, will you please let me know what kind
    of features would you like the debugger to provide. Are there any
    special/additional features that the debugger should provide for
    shell programs? How many debugging features for shell scripts are 
    already available?
    Do you think that checking for syntactic errors should be done
    by the debugger?
    Which is better - debugger in shell script or debugger written in C?

    Please e-mail your replies to me. I am planning to write one if there
    is a need for one. The most confusing thing for me is that shell
    scripts are interpreted. So, I think, I can't really use the design
    philosophy of other debuggers (dbx, sdb, etc.) for this. Can I?
    I am also not sure if I understand the measure of importance for a
    good user-interface for a debugger.

    Thanks in advance for all your help.

    Srini.