Ubuntu 18.04 show IP on login prompt /etc/issue

• cp /etc/issue /etc/issue.bak
• vi /etc/network/if-up.d/update-issue

  • #!/bin/sh
    # Add IP and MAC to /etc/issue 
     
    VERSION=$(cat /etc/issue.net)
    IPADDR=$(hostname -I | tr " " "\n" | grep -v "^$" | sort -t . -k 1,1n | head -1 | tr "\n" " ")
    MAC=$(cat /sys/class/net/*/address | head -n 1)
    
    echo "$VERSION \\\n \\l $IPADDR $MAC\n" > /etc/issue

• chmod 0755 /etc/network/if-up.d/update-issue

test

• /etc/network/if-up.d/update-issue
• cat /etc/issue