背景：ubuntu 16.04
安装rar/unrar时提示错误：
sudo apt-get install unrar Reading package lists... Done Building dependency tree Reading state information... Done Package unrar is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'unrar' has no installation candidate
解决方法：
打开https://www.rarlab.com/download.htm
下载RAR 5.71 beta 2 for Linux(根据系统选取32位/64位下载)
如何判断系统是32位/64位：
root# getconf LONG_BIT 64 # 64位系统
安装：
tar -xzpvf rarlinux-x64-5.7.1b2.tar.gz cd rar make
输入make会提示:
root:/home/work/rar# make mkdir -p /usr/local/bin mkdir -p /usr/local/lib cp rar unrar /usr/local/bin cp rarfiles.lst /etc cp default.sfx /usr/local/lib
