Requirements: Docker, git
git clone https://github.com/TCIRC/circsay.git
cd circsay
./run.sh
`ls`
to print directory contents`cat flag.txt`; echo a
to print flag and escape cowsay- flag.txt is cow language to output the flag, google
cow language online
and paste the code into the first search result - the flag is
FLAG{why_u_rce_my_machine_u_bad_bad_guy_sub_to_nekomata_okayu_now}