I wanted to add an SSH key to a new minimal Debian VM install, but attempting to add the key resulted in a No such file or directory error.
# sudo cat id_rsa.pub >> .ssh/authorized_keys cat: id_rsa.pub: No such file or directory
The error was the result of the non-existent authorized_keys file which is where SSH key happens to be stored.
If we look inside the ~/.ssh directory you will notice the missing authorized_keys file.
# cd ~/.ssh # ls known_hosts
To be able to store the SSH key create the missing authorized_keys in the right location and with the right permission.
Move to the directory where key files are stored for the user.
# cd ~/.ssh
Create necessary file.
# touch authorized_keys
Assign permission to file.
# chmod 600 authorized_keys
Copy SSH key to authorized_keys file.
# cat id_rsa.pub >> .ssh/authorized_keys
Optional, but I recommend removing the key since its no longer needed.
# rm id_rsa.pub
Restart the service.
# sudo service ssh restart