1. 终端

1.1. 硬件终端

计算机终端是可以用于将数据输入到计算机或计算系统中以及从中显示或打印数据的电子或机电硬件设备.

早期的终端实际上是一台独立于计算机的机器(teletypewriter,teleprinter, or TTY), 也被称为电传打字机, 下图是一个例子:

Teletype Model 33

不过这种终端现在基本上没人用了, 现在大家用的其实都是终端模拟器, 都是模拟出来的.

1. Level 22

1.1. 关卡目标

A program is running automatically at regular intervals from cron, the time-based job scheduler. Look in /etc/cron.d/ for the configuration and see what command is being executed.

NOTE: Looking at shell scripts written by other people is a very useful skill. The script for this level is intentionally made easy to read. If you are having problems understanding what it does, try executing it to see the debug information it prints.

1.2. 解决方案

这关明显是上一关的升级版…

题目还说了得学会看懂别人写的 shell 脚本, 也就是说这题涉及到了些 shell 脚本的知识