1.安装
apt-get install graphviz
如果报错说缺少依赖文件，则使用apt自动安装依赖项
apt-get -f install
我在安装中报错：
dpkg: unrecoverable fatal error, aborting:
fork failed: Cannot allocate memory
重新执行安装命令时，出现新错误
E: dpkg was interrupted, you must manually run 'dpkg --configure -a' to correct the problem.
按照提示执行
dpkg --configure -a
又报错
Errors were encountered while processing: graphviz:i386
网上搜索后，尝试如下解决
aptitude update
报错：
The program 'aptitude' is currently not installed. You can install it by typing: apt install aptitude
根据提示，执行
apt install aptitude
报错
You might want to run 'apt-get -f install' to correct these:
根据提示执行
apt-get -f install
完成，重新安装 graphviz
apt-get install graphviz
成功
可见，错误原因是aptitude没安装。
2.使用
参考：https://zhuanlan.zhihu.com/p/21993254
https://www.tianmaying.com/tutorial/graphviz
The program 'aptitude' is currently not installed. You can install it by typing:apt install aptitude