feat: redesign the project structure

home/linux/common/ssh.nix

@@ -0,0 +1,39 @@
+{
+  pkgs,
+  ...
+}: {
+  programs.ssh = {
+    enable = true;
+
+    # all my ssh private key are generated by `ssh-keygen -t ed25519 -C "ryan@nickname"`
+    # the config's format:
+    #   Host —  given the pattern used to match against the host name given on the command line.
+    #   HostName — specify nickname or abbreviation for host
+    #   IdentityFile — the location of your SSH key authentication file for the account.
+    # format in details:
+    #   https://www.ssh.com/academy/ssh/config
+    extraConfig = ''
+      Host 192.168.*
+        # allow to securely use local SSH agent to authenticate on the remote machine.
+        # It has the same effect as adding cli option `ssh -A user@host`
+        ForwardAgent yes
+        # romantic holds my homelab~
+        IdentityFile ~/.ssh/romantic
+        # Specifies that ssh should only use the identity file explicitly configured above
+        # required to prevent sending default identity files first.
+        IdentitiesOnly yes
+
+      Host github.com
+          # github is controlled by gluttony~
+          IdentityFile ~/.ssh/gluttony
+          # Specifies that ssh should only use the identity file explicitly configured above
+          # required to prevent sending default identity files first.
+          IdentitiesOnly yes
+    '';
+
+    # use ssh-agent so we only need to input passphrase once
+    # run `ssh-add /path/to/key` for every identity file
+    # check imported keys by `ssh-add -l`
+    # TODO `ssh-add` can only add keys temporary, use gnome-keyring to unlock all keys after login.
+  };
+}