С systemd вы можете сделать systemctl edit getty@ с чем-то вроде:
[Service]
ExecStartPre=-/bin/bash -c '[ ! -f /etc/.issue.orig ] && cp /etc/issue /etc/.issue.orig; int=`ls /sys/class/net|grep enp|head -1`; sed -r "s/\\\\\\n/[\\\\\\4\{$$int\}]/" < /etc/.issue.orig > /etc/issue'
Затем systemctl daemon-reload && systemctl restart getty@tty1