Specify private key in SSH as string

Question

I can connect to a server via SSH using the -i option to specify the private key:

ssh -i ~/.ssh/id_dsa user@hostname 

I am creating a script that takes the id_dsa text from the database but I am not sure how I can give that string to SSH. I would need something like:

ssh --option $STRING user@hostname 

Where $STRING contains the value of id_dsa. I need to know the --option if there is one.

Answer 1

Try the following:

echo $KEY | ssh -i /dev/stdin username@host command 

The key doesn't appear from a PS statement, but because stdin is redirected it's only useful for single commands or tunnels.

Answer 2

There is no such switch - as it would leak sensitive information. If there were, anyone could get your private key by doing a simple ps command.

EDIT: (because of theg added details in comment)

You really should store the key in to a temporary file. Make sure you set the permissions correctly before writing to the file, if you do not use command like mktemp to create the temporary file.

Make sure you run the broker (or agent in case of OpenSSH) process and load the key using <whatever command you use to fetch it form the database> | ssh-add -