I Hate to echo unique text by php function on multiple pages

At first sorry if there is answer for my question, and for poor english. I have cms with .twig files, and i want on multiple pages (categories) put unique text. Only option is to edit pages.twig file by adding function "is url is abc echo

if url is def echo and so going on.

I found "if $host is..." function but shouldn't it be something like if url is in my case?