Scheduling recurring jobs on Unix/Linux systems Which program is traditionally used to schedule commands or scripts to run at specific times and dates automatically?

Introduction / Context:
Automating system tasks is a cornerstone of Unix/Linux administration. Whether rotating logs, running backups, or refreshing caches, administrators rely on a time-based job scheduler to execute commands without manual intervention. This question checks the recognition of the standard scheduler.

Given Data / Assumptions:

• The operating system is Unix/Linux.
• We need a recurring, time-based scheduling mechanism.
• We are not referring to one-off, immediate execution tools.

Concept / Approach:

cron is the de facto daemon for periodic job scheduling. Users define crontab entries specifying minute, hour, day-of-month, month, and day-of-week fields followed by the command to run. The system variant, /etc/crontab or files in /etc/cron.d, supports specifying the user as well. Complementary tools include at for one-time jobs and anacron for scheduling on systems that are not always on.

Step-by-Step Solution:

Verification / Alternative check:

Confirm that the cron daemon is running (for example, systemctl status crond or cron depending on the distro). Test with a simple scheduled echo redirected to a file and verify it appears at the expected time.

Why Other Options Are Wrong:

• vi: a text editor; not a scheduler.
• Outlook: an email and calendar client on other platforms; unrelated to Unix scheduling.
• Scheduler: too generic; not a standard Unix command name.
• None of the above: incorrect because cron is correct.

Common Pitfalls:

Incorrect crontab field order, environment differences (PATH) within cron jobs, and forgetting to redirect output or specify absolute paths to commands and scripts.

Final Answer:

cron