When I do on my Manjaro Deepin Linux x64:
# npm i ipfs --global
I get
npm ERR! code 128
npm ERR! Command failed: /usr/bin/git clone --depth=1 -q -b master git://github.com/dignifiedquire/webcrypto-shim.git /root/.npm/_cacache/tmp/git-clone-e9adc753
npm ERR! fatal: não foi possÃvel criar os diretórios superiores de '/root/.npm/_cacache/tmp/git-clone-e9adc753': Permission denied
npm ERR!
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2017-08-22T13_36_21_135Z-debug.log