In the downloaded purse the termination of team .xz
And in team tar -xvzf vivo-0.12.1.2-ubuntu14.04.tar.gz the termination .gz
It is impossible to continue installation.
EDIT: Ignore the below, you should be downloading version 0.12.1.7 anyway. Go to https://github.com/vivocoin/vivo/releases/ and download from there.If the file is compressed with xz, you need to use xz to decompress it, not just rename the file.
To check run:
file tar -xvzf vivo-0.12.1.2-ubuntu14.04.tar.gz
If it reports
vivo-0.12.1.2-ubuntu14.04.tar.gz: gzip compressed data, from Unix, last modified:...
then it is gzip compressed.
If instead it reports:
vivo-0.12.1.2-ubuntu14.04.tar.gz: XZ compressed data
You need to run:
tar -xvJf vivo-0.12.1.2-ubuntu14.04.tar.gz
You may need to install xz first, in which case do the below first:
sudo apt-get install xz-utils