在ubuntu安装rstudio时，碰到依赖未安装的报错：
	 dpkg: dependency problems prevent configuration of rstudio:
	 rstudio depends on libssl-dev; however:
	 Package libssl-dev is not installed.
	 rstudio depends on libpq5; however:
 	 Package libpq5 is not installed.
开始的时候会想到根据依赖名称去下载安装，很繁琐，而且有版本问题。
后面直接安装openssl——运行：
	 sudo apt-get install openssl
会遇到同样的缺少依赖报错，但给出了提示，运行结果如下：
	The following packages have unmet dependencies:
 	rstudio : Depends: libssl-dev but it is not going to be installed
    Depends: libpq5 but it is not going to be installed
    E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
然后再运行：
    sudo apt --fix-broken install
会发现它会自动安装缺少的依赖。
最后运行命令，rstudio安装成功：
	sudo apt-get install openssl
	sudo dpkg -i r.deb