Line editing in dash

In bash or mksh it is possible to move around the typed line word by word, using shortcuts such as ESCB.

That doesn't work in ksh or dash. As far as I understand from googling, this has something to do with readline support, however nowhere I've seen it mention how to enable support for dash.

That's the core of my question: How to enable line navigation for dash

If you definitely want dash plus command-line editing and history, you can use rlwrap:

rlwrap dash

Suggestion:

rlwrap -cmD2 dash

To use rlwrap, you'll have to:

sudo apt-get install rlwrap

The short answer is:

You don't.

dash is a direct descendent of the Almquist Shell (ash). ash never featured line editing support, and neither does dash. Busybox ash does, so if you must an ash variant for some reason and have line editing, etc., use Busybox ash. Nobody's going to bother with adding readline support, since dash's primary use is for running shell scripts.

Unless, of course, you're willing to code support for readline in dash, and maintain such a patch yourself...

The long answer is:

Compile with libedit

If you look at dash's manpage:

-V vi           Enable the built-in vi(1) command line editor
                (disables -E if it has been set).

-E emacs        Enable the built-in emacs(1) command line editor
                (disables -V if it has been set).

These only work if dash was compiled with --with-libedit. It isn't, neither in Ubuntu, nor, apparently, in Debian.

You can build it thus:

git clone https://git.kernel.org/pub/scm/utils/dash/dash.git
cd dash 
./autogen.sh 
./configure --with-libedit 
make

Then run:

src/dash -E

You should be able to use the arrow keys to edit the current command.