kazulog@sv1:~$ cat /etc/os-release | head -2
PRETTY_NAME="Ubuntu 26.04 LTS"
NAME="Ubuntu"
kazulog@sv1:~$ cat /etc/inetd.d/hello
# 自作サービス: 10013 番につながると /usr/local/bin/hello.sh を実行する
hello	stream	tcp	nowait	nobody	/usr/sbin/tcpd	/usr/local/bin/hello.sh
kazulog@sv1:~$ grep -n hello /etc/services
366:hello		10013/tcp			# 検証用の自作サービス
kazulog@sv1:~$ cat /usr/local/bin/hello.sh
#!/bin/sh
echo "hello from inetd on $(hostname)"
kazulog@sv1:~$ sudo systemctl restart inetutils-inetd
kazulog@sv1:~$ sudo ss -tlnp 'sport = :10013'
State              Recv-Q             Send-Q                         Local Address:Port                            Peer Address:Port             Process
LISTEN             0                  10                                   0.0.0.0:10013                                0.0.0.0:*                 users:(("inetutils-inetd",pid=4189,fd=7))