Install Mercurial 1.0.2 on Ubuntu 8.1 server using source code package

(Using root recommended)

If compiler and python not installed:

apt-get install build-essential python-dev
tar xvf mercurial-1.0.2.tar.gz
cd mercurial-1.0.2
make install

To verify,

hg debuginstall

Hopefully, you'll see

Checking encoding (UTF-8)...
Checking extensions...
Checking templates...
Checking patch...
Checking commit editor...
Checking username...
No username found, using 'root@hubuntus' instead
(specify a username in your .hgrc file)
No problems detected

And that's it.

Ref: http://www.selenic.com/mercurial/wiki/index.cgi/UnixInstall