Technology Tales

Adventures & experiences in contemporary technology

Automated entry of SSH passwords

17th February 2022

One thing that is very handy for shell scripting is to have automated entry of passwords for logging into other servers. This can involve using plain text files, which is not always ideal so it was good to find an alternative. The first step is to use the keygen tool that comes with SSH. The command is given below and the -t switch specifies the type of key to be made, RSA in this case. There is the option to add a passphrase but I decided against this for sake of convenience and you do need to assess your security needs before embarking on such a course of action.

ssh-keygen -t rsa

The next step is to use the ssh-copy-id command to generate the keys for a set of login credentials. For this, it is better to use a user account with restricted access to keep as much server security as you can. Otherwise, the process is as simple as executing a command like the following and entering the password at the prompt for doing so.

ssh-copy-id [user ID]@[server address]

Getting this set up has been useful for running a file upload script to keep a web server synchronised and it is better to have the credentials encrypted rather than kept in a plain text file.

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