Download the latest version from the official website:
$ wget http://hea-www.harvard.edu/saord/download/ds9/linux64/ds9.linux64.6.0.tar.gz $ tar -xvzf ds9*.tar.gz $ chmod 755 ds9 $ sudo mv ds9 /usr/local/bin
(The wget line is an example.) This will install DS9 under /usr/local/bin.
