For example, I am using M-x occur, and want to edit the default regexp (which is shown in the prompt), and then enter your edited regexp.
can we edit the default value ^ *[[:digit:]]\.[[:digit:]]\.[[:digit:]] + to create a new input e.g. deleting + at the end to get ^ *[[:digit:]]\.[[:digit:]]\.[[:digit:]] ?
The problem is how to move the default value into the editable region.
Thanks.

occur. – Dan Feb 14 '15 at 14:49