feat: add README for SSH agent and known_hosts management scripts

docker-rsync/README.md

@@ -0,0 +1,40 @@
+# Scripts
+
+Shell-scripts to help with managing SSH agents and known hosts files.
+
+### SSH Management
+
+#### ssh-init
+This command create the ``$HOME/.ssh`` folder with default permissions ``700``.
+
+### SSH-Agent Management
+
+#### agent-start
+This command starts the SSH agent, if it isn't already started (SSH_AGENT_PID set or ssh agent ID file found).
+It takes one optional argument, for the name of the agent to be started. Defaults to "default".
+This program needs to be source'd to work correctly.
+`source agent-start "default"`
+
+#### agent-stop
+This command stops the SSH agent, if it is started (SSH_AGENT_PID set or ssh agent ID file found).
+It takes one optional argument, for the name of the agent to be stopped. Defaults to "default".
+`agent-stop "my-agent-name"`
+
+#### agent-add
+This command adds a key to the currently running SSH agent. The key is taken from stdin, and the agent used is that in SSH_AGENT_PID.
+
+#### agent-askpass
+This command is called by ssh-add when the [SSH_ASKPASS](https://man.openbsd.org/ssh-add.1#ENVIRONMENT) variable is set active. The command returns the SSH_PASS to [ssh-askpass(1)](https://man.openbsd.org/ssh-askpass.1).
+
+This command is ignored by ssh-add if the key does not require a passphrase.
+
+### known_hosts management
+
+#### hosts-init
+This command creates the known_hosts file (``$HOME/.ssh/known_hosts``) with default permission ``600``.
+
+#### hosts-add
+This command adds an entry to the known hosts file, and ensures its permissions are correct. It takes one argument, which is the new key to add.
+
+#### hosts-clear
+This command truncates the known_hosts file.