Sass是一種css的開發工具，它的安裝依賴Ruby，沒有安裝Ruby的請先安裝Ruby。
假定你已經安裝了Ruby，則可以直接執行如下語句進行安裝。
gem install sass
常見錯誤提示：
1、ERROR: While executing gem ... (OpenSSL::SSL::SSLError)
hostname "gems.ruby-china.org" does not match the server certificate
解決辦法：
執行命令，查看數據源
gem source -l
結果
*** CURRENT SOURCES *** https://ruby.taobao.org/ https://gems.ruby-china.org
則可以刪除多餘的
gem sources --remove https://ruby.taobao.org/ sudo gem update --system
然後重新安裝。
2、ERROR: SSL verification error at depth 1: unable to get local issuer certificate (20)
ERROR: You must add /O=Digital Signature Trust Co./CN=DST Root CA X3 to your local trusted store
Fetching: ffi-1.9.18.gem ( 32%)ERROR: SSL verification error at depth 2: self signed certificate in certificate chain (19)
ERROR: Root certificate is not trusted (/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA)
ERROR: While executing gem ... (OpenSSL::SSL::SSLError)
hostname "gems.ruby-china.org" does not match the server certificate
3、ERROR: SSL verification error at depth 1: unable to get local issuer certificate (20)
ERROR: You must add /O=Digital Signature Trust Co./CN=DST Root CA X3 to your local trusted store
Fetching: ffi-1.9.18.gem (100%)
Building native extensions. This could take a while...
Successfully installed ffi-1.9.18
ERROR: SSL verification error at depth 2: self signed certificate in certificate chain (19)
ERROR: Root certificate is not trusted (/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA)
Fetching: rb-inotify-0.9.10.gem (100%)
Successfully installed rb-inotify-0.9.10
Fetching: sass-listen-4.0.0.gem (100%)
Successfully installed sass-listen-4.0.0
Fetching: sass-3.5.1.gem (100%)
ERROR: While executing gem ... (Errno::EPERM)
Operation not permitted - /usr/bin/sass
遇到以上錯誤 2和3的解決辦法
sudo gem install -n /usr/local/bin sass
查看
sass -v
則會正確顯示Sass版本號。
2017年12月28日更新：
Mac更新系統後，Ruby由2.0升級到2.3，再次使用Sass時候，發現報錯。
於是決定升級SaaS，重新安裝時遇到錯誤。最後找到解決方案：
先安裝libgmp-dev，再重新安裝即可。
brew install libgmp-dev sudo gem install -n /usr/local/bin sass