環境變數設定

for ubuntu:
$vim /etc/environment

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
LANGUAGE="zh_TW:zh:en_US:en"
LANG="zh_TW.UTF-8"
CLASSPATH=...(JAVA)
新增path的話以冒號區隔:
變數值最好加上雙引號""

立即生效
$source 檔案名稱(/etc/environment)