What shows on the screen is just CCNA01# ; as is typical for many devices, though, this prompt actually embeds invisible control characters.

屏幕上所显示的是 CCNA01# ；对于许多设备来说，这是非常典型的，这个提示符实际上嵌入了一些不可见的控制字符。

youdao

Hidden in the Net is the mystery of the Invisible Hand — control without authority.

暗藏在网络之中的是神秘的看不见的手——一种没有权威存在的控制。

youdao

The daily work of rolling out malaria control programmes is invisible. It's not front page news.

日常开展疟疾控制规划工作不是头版新闻，往往不为人知。

youdao

Nearly everything modern medicine does to control these invisible killers, further optimizes their resistance to our drugs and combat strategies, and hence their proliferation.

FORBES: The Best and Worst of Times: Killer Vegetables, Plunging Markets, Infinite Nature

Fifth-generation aircraft are invisible to radar, have advanced flight and weapons control systems and can cruise at supersonic speeds, officials say.

BBC: India to buy advanced fighter jets from Russia

This invisible network of mutual back-scratching made it difficult for anyone outside the military to control it - or even understand it.

CNN: A Question Of Loyalty