Below is a comprehensive summary in English, covering all the topics from the provided file (Chapter 5, Part 2 on Process Management and Task Scheduling). This summary includes command explanations, code examples, and the concepts you need to know in order to pass your exam. Treat this as your all-in-one study guide.

1. Overview: Task Scheduling in Linux

In Linux, there are two main ways to schedule tasks (jobs):

1. at: Schedules a task once at a specific time (or date).
2. crontab (Cron jobs): Schedules tasks repetitively, at regular intervals (daily, weekly, monthly, etc.).

2. Installing the at Command

Before using at, you may need to install it on your system (e.g., on Ubuntu/Debian-based systems):

sudo apt install at

3. The at Command

3.1 Purpose

• The at command is used to schedule one-time tasks for execution at a specific date and/or time.

3.2 Basic Syntax

at [time] [date/day]

• time is mandatory.
• date/day is optional. If omitted, the system assumes the current date.

3.3 Usage Example

1. Type:

or

```bash
at 10:30
```

```bash
at 10:30 tomorrow
```