can you please expalin these command lines in brief

1)openssl genpkey -algorithm RSA -out myprivkey1.pem -pkeyopt rsa_keygen_bits:2048

2)openssl rsa -pubout -in myprivkey1.pem -out mypubkey1.pem

3)cat plain.txt | openssl rsautl -encrypt -pubin -inkey mypubkey1.pem >

cipher.txt

4)cat cipher.txt | openssl rsautl -decrypt -inkey myprivkey1.pem

5)openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout my.key

-out my.crt