When you want to ssh into a server, and you didn’t name your private key file id_rsa, all you need to do to make ssh work is to specify the location of your private key file with the -i option of the ssh command:
$ ssh -i ~/.ssh/my_key_file username@servername
I just tested that and it works fine. The man page for the scp command shows that it also uses the -i option to specify the private key file. That’s actually my reason for using this technique, I want to scp a file to a Raspberry Pi device I have on my network, so I now use this command to make that happen:
$ scp -i ~/.ssh/rpi_rsa Notes.data pi@10.0.0.23:./
I originally wrote about the process of configuring your client and server to ssh login without a password, and I can confirm that that tutorial still works, but I didn’t write about this process at that time. You can find more information about this at askubuntu.com.