$ sudo apt-get update
$ sudo apt-get install libtext-markdown-perl 

libtext-markdown-perl is installed in your system.

Make ensure the libtext-markdown-perl package were installed using the commands given below,

$ sudo dpkg-query -l | grep libtext-markdown-perl *

You will get with libtext-markdown-perl package name, version, architecture and description in a table

libtext-markdown-perl package basic information: