esoF*ck 2

We have a file linked to the challenge :

eso-file

It seems to be brainfuck, so we can go on https://copy.sh/brainfuck/ and we paste the file We optain this output :

Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook. Ook.

Ook. Ook. ... (truncated)

It seems to be another esoteric langage, so we search for it and we can find it's the ook langage. We go on https://www.dcode.fr/ook-language and we paste the text and we optain :

grepCTF{3sot3r1c_l4ngu4g3s_4r3_0k!}