这个问题我的原因是
网卡名称带有空格。命令无法显示。加上双引号就可以啦。
[root@liruilong ~]# nmcli connection show
NAME UUID TYPE DEVICE
System eth0 5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 ethernet eth0
[root@liruilong ~]# nmcli con show System eth0 Error: System - no such connection profile.
解决办法：
[root@liruilong ~]# nmcli con show "System eth0" connection.id: System eth0 connection.uuid: 5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 connection.stable-id: -- connection.type: 802-3-ethernet connection.interface-name: eth0 connection.autoconnect: yes connection.autoconnect-priority: 0 connection.autoconnect-retries: -1 (default) connection.multi-connect: 0 (default) connection.auth-retries: -1 connection.timestamp: 1600489843
numcli con show （Error: System - no such connection profile.）报错问题解决
原文：https://www.cnblogs.com/liruilong/p/13695772.html