#!/usr/bin/ksh is my favourite shell .

Ksh rocks :-)

i agree with amsct KSH is great..

Quite happy with BASH, although I haven't used KSH since the mid-90's. The main thing missing from BASH is KSH's !(...) file glob feature. A friend recently showed me zsh, and it's come a long way in the last 10 years. I like the pop-up / browse filename feature. Very sleek.

So in general I break it down as follows:

zsh : interactive use (but I still don't use it every day)
bash : advanced all-purpose shell-scripting
ksh : when you have to be portable and sh compatibility means pulling hair.

Cool and *yawn*. I implemented something like this in BASH. Since I use screen I often have multiple histories, so I created my own search/merge system. Sometimes a command I'm looking for is only relevant to Solaris, sometimes to Linux, sometimes to my Linux cluster. For this, I keep different histories separated by host-type and tty.

Does that reflect lack of computing power or lack of complexity?
If it's the former:

1036 9716 0.0 0.1 7532 3016 ? Ss Jul26 8:50 SCREEN -c
1036 30119 0.0 0.1 10520 3944 ? Ss Jul24 41:53 SCREEN

That's 50 minutes -- 0.1% -- of computing time in a month.

If it's the latter, well, it all depends on how much you use the command line, I guess, and how much you like moving your hands from the mouse to keyboard and back. On a laptop or special keyboards, it's only a slight gain in productivity.