> I would like to update a site with httrack
> that I created originally with winttrack ?
httrack --update -O <path> should do the trick - but 
backup your project folder before doing tests

Copy (in binary mode) the entire folder and then to 
update it, enter into it and do a
httrack --update -O ./ 

See the FAQ:

"Copy (in binary mode) the entire folder and then to 
update it, enter into it and do a
httrack --update -O ./ 

Note: You can then safely replace the existing folder 
(under Windows) with this one, because the Linux/Unix 
version did not change any options
Note: If you often switch between Windows/Linux with 
the same project, it might be a good idea to edit the 
hts-cache/doit.log file and delete old "-O" entries, 
because each time you do a httrack --update -O ./ an 
entry is added, causing the command line to be long "