[gana@sirius ~]$ bash --version
GNU bash, version 5.2.15(1)-release (x86_64-redhat-linux-gnu)

I was experimenting and trying to assign a variable using a heredoc/herestring.

Found this: https://stackoverflow.com/questions/1167746/how-to-assign-a-heredoc-value-to-a-variable-in-bash

Liked this solution below, which is multi-line but a single command:
```
VAR=$(cat <<'END_HEREDOC'
abc'asdf"
$(dont-execute-this)
foo"bar"''
END_HEREDOC
)

# this will echo variable with new lines intact
echo "$VAR"
# this will echo variable without new lines (changed to space character)
echo $VAR
```

It works ! Value assigned to variable is correct. But, ...

Say one presses up-arrow key to go up history back to just executed multiline command.
An extra newline (blank line) appears between the closing heredoc string terminator and the closing parenthesis ')'

Press enter to run again and press up-arrow and there will be 2 blank lines.
Repeat and there will be three blank lines.
.. and so on, it get longer.
 
The history command shows that blank-line elongated longer versions of the same multiline command are being appended to the history.