You can use sleep and clear commands in your script as following:

for word in $(< read)
do
    echo "$word"
    sleep 1
    clear
done

Explanation:

The sleep command make delay for a specified amount of time (in seconds). With sleep 1 delay would be for 1 second. You can change for more time delay by incrementing the second parameter or for delaying less than 1 second divide it to low units; Like sleep .1 for 1/10 second delay or sleep .001 for 1/1000 second delay and etc.

The clear command clear the terminal screen.

Even better you can do this through below awk command:

awk '{i=1; while(i<=NF){ print $((i++)); system("sleep 1; clear") }}' read

Explanation:

In awk, the NF specifies the total number of fields in the current input record/line, so by using a variable as a counter (i) and looping over it, we are printing all of them from 1st position to the end of them (NF). Then by using the system("sleep 1; clear") part, we are telling to awk to calling the system commands to sleeping for 1 second and clearing the screen.

In above we are displaying the input file as word by word. If you are going to display it line by line add IFS=$'\n' in the script like:

IFS=$'\n'
for word in $(< read)
do
    echo "$word"
    sleep 1
    clear
done

And change the awk command like:

awk '{ $0; system("sleep 1; clear") }1' read

• $0 specifies the current line. and the 1 on end enables the default awk's print command.

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.