是否有适用于 Ubuntu 的应用程序，它会在规定的时间（例如 30 分钟）后锁定计算机。我需要它来限制孩子们看动画片的时间。例如，观看 30 分钟，然后 PC 锁定，需要父母解锁。
对于 Windows，我使用了 Eyes Relax 应用程序，它显示黑屏和绿色进度条（解锁 PC 的剩余时间）并且需要密码才能覆盖锁定。
双击 viber.deb 没有安装它，所以我尝试了终端，它也会出现错误（用谷歌翻译翻译）：
dmitriy @ dmitriy-ub16x64: ~ / Downloads $ sudo dpkg -i viber.deb
[sudo] password for dmitriy:
Selecting a previously unselected viber package.
(Reading the database ... at the moment there are 585858 files and directories installed.)
Preparing for unpacking viber.deb ...
Unpacked viber (7.0.0.1035) ...
dpkg: package dependencies do not allow you to configure the viber package:
viber depends on gstreamer1.0-plugins-ugly, however:
The package gstreamer1.0-plugins-ugly is not installed.
viber depends on gstreamer1.0-libav, however:
The package gstreamer1.0-libav is not …