[guest@localhost ~]$ httrack --mirror <http://unity-linux.org> -O ./ul/
Segmentation fault
[guest@localhost ~]$ httrack <http://unity-linux.org> -O ./ul/
Segmentation fault
[guest@localhost ~]$

Please leave a better example if that's not correct.

[guest@localhost ~]$ ls -R ul/           
ul/:
hts-log.txt
[guest@localhost ~]$ more ul/hts-log.txt 
[guest@localhost ~]$

Thanks for your attention to the matter.