updated notes

src/rhcsa.md

@@ -410,6 +410,11 @@ fi
 ### Change the grub2 configuration
 ```bash
 sudo grub2-mkconfig -o /boot/grub2/grub.cfg # Create a new grub configuration file
+
+sudo nano /etc/default/grub # Edit the grub configuration file
+
+# Add the following line to the grub configuration file:
+GRUB_CMDLINE_LINUX="quiet splash"
 ```
 
 ### dmesg
@@ -462,4 +467,38 @@ runlevel # Display the current run level
 sudo systemctl get-default # Display the default target
 sudo systemctl set-default runlevel3.target # Set the default target to runlevel3.target
 sudo telinit 3 # Change to runlevel 3
+```
+
+## Manage SSH Connections
+
+### ssh
+```bash
+ssh user@host # Connect to the host as the user
+
+ssh -p 2222 user@host # Connect to the host as the user on port 2222
+
+ssh -i /path/to/private_key user@host # Connect to the host as the user using a private key
+
+ssh-copy-id user@host # Copy the user's public key to the host
+
+ssh-keygen -t ed25519 -C "comment" -f ~/.ssh/id_ed25519 -N "" # Generate a new ed25519 key
+
+ssh-keygen -t rsa -b 4096 -C "comment" -f ~/.ssh/id_rsa -N "" # Generate a new rsa key
+```
+
+### sshd_config
+```bash
+sudo nano /etc/ssh/sshd_config # Edit the sshd configuration file
+
+# Add the following line to the sshd configuration file:
+Port 2222
+
+sudo systemctl restart sshd # Restart the sshd service
+```
+
+## NFS & NTP
+
+### NFS
+```bash
+sudo nano /etc/exports # Edit the exports file
 ```