tlmgr install [Package]
where [Package]
found in http://www.ctan.org/ or its mirror sites.
recently cannot use the command above but great hint found! http://tex.stackexchange.com/questions/313768/tlmgr-unknown-directive
saying get update-tlmgr-latest.sh
from https://www.tug.org/texlive/tlmgr.html then run as root
# sh update-tlmgr-latest.sh
hints from https://texwiki.texjp.org/?LaTeX%E5%85%A5%E9%96%80%2F%E5%90%84%E7%A8%AE%E3%83%91%E3%83%83%E3%82%B1%E3%83%BC%E3%82%B8%E3%81%AE%E5%88%A9%E7%94%A8
kpsewhich style.sty
to find out where the package is installed
sudo mktexlsr
to update directory tree after manual-install a package
in tlmgr
case this is not required