Code:
any2epub --margin-top=0 --margin-bottom=0 --margin-right=0 --margin-left=0 "nameofbook.prc"
and then there is also....
Code:
mobi2oeb "nameofebook.prc"
Code:
html2epub --margin-top=0 --margin-bottom=0 --margin-right=0 --margin-left=0 "nameofebook.opf"
The above two must be done in order. But try the first one before the last two.