I can use dpkg-reconfigure dash to switch sh to ether bash or dash.
My favorite shell isn't bash (unlike so many other people...) it's The Z Shell (zsh).
How would I switch sh from dash to zsh (yes I am aware of /etc/passwd and have already edited it and am aware of the slowed boot times). I don't have a GUI just command-line.

You should not pick /bin/sh based upon what you like.
You should pick /bin/sh based upon what best supports your system scripts (current and future) as provided by your distribution. Most often that means not messing with it.

You select your OWN shell based upon what you like, and let your SCRIPTS run the one that has the features you like using the '#!' line.


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That said, it IS possible to change it to any valid shell (or invalid shell, but PLEASE do not do that!) manually. IT is a simple link.

Check the man page and info documents for 'ln' before starting any manual changes, and do understand that you can disable your system if you mess it up.

Yeah, what wpeckham said.
Your system was configured to use bash (or whatever) for reasons understood by the developers. That should have NO influence on what shell or scripting language you prefer to use. If you want to write your scripts using zsh, that should be perfectly fine, and should be done independently of existing system scripts. The default shell used by each user is configurable, as you have already discovered.

--- rod.

Anything invoking a shell as sh should only posix features (not to mention that the person could of used /bin/bash or /bin/dash)! ZSH checks to see if it is ran as sh then emulates it as close as possible. Debian is currently just my toy os (occupying only 41Gs on my HD) easily reinstalled, reconfigured (with scripts hosted on the Ubuntu Partition), and deleted. (with less than 500 packages installed and about 400 of them are on the install media the others, again, downloaded to a folder on the Ubuntu partition; Installing the remaining packages is not a problem ) Now to make you happy I'll try it in a qemu test os first.
Now how do I change /bin/sh?

/bin/sh is nothing more than a symlink to the shell in use. Just let it point to /bin/zsh to achieve what you want.

...or perhaps 'chsh' is what you are after....