You can install this with cargo with the command
cargo install aesthetic
You can install cargo with
curl https://sh.rustup.rs -sSf | sh
If you just want a specific string aesthetic:
$ aesthetic "FEELIN' FINE"
ＦＥＥＬＩＮ＇ ＦＩＮＥ
Or you can use pipes:
$ doggo "yung doge" | aesthetic
ｙｕｎｇ ｄｏｇｅ ｉｓ ａ ｇｏｏｄ ｇｉｒｌ！