EMACS: Auto run a function when open a new buffer

Question

How can I auto run a function when open a new buffer, say text-scale-adjust.

Answer 1

A slightly more detailed version of abo-abo's answer:

(add-hook 'find-file-hook
          '(lambda () (text-scale-adjust 1)))

This will run for all files you visit. You can look at mode-specific hooks if you want to tailor which types of files/buffers get this treatment.