at
Overview
The at command executes commands at a specified time. It’s used for one-time task scheduling, unlike cron which handles recurring tasks.
Syntax
at [-V] [-q queue] [-f file] [-mldbv] TIMECommon Options
| Option | Description |
|---|---|
-f file |
Read commands from file |
-m |
Send mail after execution |
-l |
List pending jobs (same as atq) |
-d |
Delete jobs (same as atrm) |
-v |
Show time of execution |
-q queue |
Use specified queue |
-b |
Batch mode (run when load permits) |
-V |
Show version |
Time Specifications
| Format | Example | Description |
|---|---|---|
| HH:MM | 14:30 | Specific time |
| now + N units | now + 1 hour | Relative time |
| midnight | midnight | 00:00 tomorrow |
| noon | noon | 12:00 today |
| teatime | teatime | 16:00 today |
Key Use Cases
- Delayed execution
- One-time tasks
- Resource scheduling
- Maintenance windows
- Batch processing
Examples with Explanations
Example 1: Basic Usage
```bash at 10:00 PM command1 command2