Personally, I really like HAML. Not having to use open and close tags is a huge time saver. As a result, writing markup with HAML is much more pleasant. HAML essentially forces you to be very strict about spacing, organization, and structure. It also makes the markup easier to read. Protip: I use this pretty frequently: htmltohaml.com

The whole backend part (deployment and other scripts, business logic, web interface) is written in Perl.

Весь бэкенд (скрипты деплоя и прочие, бизнес-логика, веб-интерфейс) написан на Perl.

I use Perl to rip through log files and compare them to some signature files I have created. When I get a match, it adds the bad guy to the list of shame in MySQL.

Huge boon to productivity when coupled with Phoenix. Moreover, it has made background jobs and all the unseen aspects of a business easily abstracted.

A very expressive language, lets you say the same thing in many different ways

Knowledge collection, collation, and enrichment. Business logic.

For some internal tools like our email deliverability monitor

We use perl with rex to control our distributed systems.

I use perl on some legacy applications.

language used by phoenix framework

Elixir and Phoenix are awesome.