cat(1) ~%2F.ssh%2Fid_rsa.pub %7C ssh -i ~%2F.ssh%2Fcloudwestkey.pem centos%40vm.ip.address %27cat %3E%3E.ssh%2Fauthorized_keys%27 
concatenate files and print on the standard output
 
Concatenate FILE(s), or standard input, to standard output.

With no FILE, or when FILE is -, read standard input.
source manpages: cat