Webhttrack is in httrack-3.30.tar.gz, see default path in
install file.
I'm not a Linux specialist, but you can find some ready-made 
programs (untar and go !) depending on the kernel you use
and on your configuration. They are usually large files and
you may download the wrong one. The configure, make, make
install and make clean procedure, when it works, simplifies
(?) the programmer task and generates the best product for
the user.
 Unfortunately, it seems that Linux is a long way from being
(as dangerous and) as simple to use as Windows.