“batch” is a command-line utility that allows users to schedule the execution of commands or scripts at a later time when the system load levels permit. It provides a way to defer the execution of resource-intensive tasks to times when the system is less busy, ensuring smoother operation and optimal resource allocation.
When executing commands using “batch,” the commands are added to a queue and are not immediately executed. The actual execution of the commands is dependent on the system load levels. The system monitors its resources, such as CPU usage, memory utilization, and disk I/O, and determines when it is appropriate to execute the queued commands. This helps prevent overloading the system during peak usage periods and ensures that critical system processes are not disrupted.
To use the “batch” utility, the service “atd” (or “atrun” on some systems) needs to be running. This service is responsible for managing the execution of scheduled commands. It ensures that the queued commands are executed as soon as the system load permits, based on predefined policies or thresholds.
By utilizing “batch,” users can perform tasks that require significant system resources without impacting the overall performance and responsiveness of the system. For example, a user may schedule a large file compression or database backup operation to run during off-peak hours when the system load is typically lower. This way, the task can complete more quickly and efficiently without affecting other critical processes running on the system.
The process of using “batch” typically involves the following steps:
- Queueing the commands: Users use the “batch” command followed by the desired command or script they want to schedule for later execution. The commands are added to the queue for deferred execution.
- Monitoring system load: The system continuously monitors its load levels, including CPU usage, memory availability, and other relevant factors. When the system determines that the load is within acceptable limits, it will start executing the queued commands.
- Execution of queued commands: Once the system load permits, the queued commands are executed in the order they were added. The execution takes place automatically by the “atd” (or “atrun”) service, which manages the scheduled tasks.
It’s important to note that the specific behavior of “batch” and the scheduling policies may vary depending on the operating system and its configuration.
batch Command Examples
1. Execute commands from standard input (press Ctrl + D when done):
# batch
2. Execute a command from standard input:
# echo "./make_db_backup.sh" | batch
3. Execute commands from a given file:
# batch -f path/to/file
Summary
In summary, “batch” is a command-line utility that enables users to schedule the execution of commands or scripts at a later time when the system load levels are favorable. By deferring resource-intensive tasks to periods of lower system activity, “batch” helps ensure smoother operation and optimal resource utilization. The “atd” (or “atrun”) service is responsible for managing the execution of the scheduled tasks based on system load conditions.