nerdexam
IBM

000-221 · Question #215

Which of the following statements is true about using crontab and at to execute tasks?

The correct answer is C. User access control for both commands can be managed with .deny files in \var/adm/cron. In AIX, user access to both crontab and at is controlled through allow and deny files stored in /var/adm/cron, making this directory the central access control point for both scheduling commands.

System Management

Question

Which of the following statements is true about using crontab and at to execute tasks?

Options

  • ACommands scheduled with crontab are executed by at.
  • BBoth commands can be used to schedule a weekly task to run for a user.
  • CUser access control for both commands can be managed with .deny files in \var/adm/cron.
  • DBoth commands preserve the current environment, including the user ID and current working directory

How the community answered

(36 responses)
  • A
    17% (6)
  • B
    3% (1)
  • C
    72% (26)
  • D
    8% (3)

Why each option

In AIX, user access to both crontab and at is controlled through allow and deny files stored in /var/adm/cron, making this directory the central access control point for both scheduling commands.

ACommands scheduled with crontab are executed by at.

crontab jobs are executed by the cron daemon (crond), not by the at command; cron and at are independent scheduling subsystems with their own separate daemons.

BBoth commands can be used to schedule a weekly task to run for a user.

The at command schedules one-time future execution only and does not support recurring schedules; only crontab can schedule a task to run weekly on an ongoing basis.

CUser access control for both commands can be managed with .deny files in \var/adm/cron.Correct

AIX manages scheduling access via cron.deny and at.deny files (and their corresponding .allow counterparts) located in /var/adm/cron. Any user listed in the appropriate .deny file is blocked from using that scheduling command, providing a consistent and administrator-controlled access model for both crontab and at.

DBoth commands preserve the current environment, including the user ID and current working directory

Neither crontab nor at fully preserves the user's current environment; crontab jobs run under a minimal non-interactive shell and do not inherit the user's current working directory or full set of environment variables.

Concept tested: Access control for crontab and at via deny files

Source: https://www.ibm.com/docs/en/aix/7.3?topic=c-crontab-command

Topics

#crontab#at command#task scheduling#access control

Community Discussion

No community discussion yet for this question.

Sign up to join the discussion
Full 000-221 Practice