107.2 Automate System Administration Tasks By Scheduling Jobs Flashcards
Alias for batch command.
at -b
cats the details of the job to standard output.
at -c [job ID]
Two commands to list pending jobs.
at -l
atq
at argument to never send mail to user.
at -M
Command to execute job at specified time.
at -t [time]
Command to show when a batch job will run.
at -v
The daemon that runs jobs queued by at.
atd
Command to set time to wait between batch jobs.
atd -b
Command to process at/batch queue only once.
atd -s
Type of job that executes when the specified load level permits.
batch
Command to delete cron job number 7.
atrm 7
Type of jobs that can run simultaneously with complex scheduling.
at jobs
Type of jobs that run sequentially when system load is low.
batch jobs
How to restrict cron jobs from sending an email to the user?
Append >/dev/null 2>&1 to the end of the crontab entry
What must be at the end of each crontab entry?
A newline character
Command for users to edit their crontab file.
crontab
Command to remove the user’s crontab file.
crontab -r
crontab file format:
minute, hour, day of month, month of year, day of week, username, and command
In crontab, what happens if both day of month and day of week are specified?
This creates an or condition, both will be executed.
Commands that are best suited for running a command once.
at
batch
Command best suited for running a command on a repeating interval.
crontab
Command used to execute cron jobs periodically, with a frequency specified in days and a wait time in minutes, and will run jobs if missed?
anacron
Path to the system cron table
/etc/crontab
Path to files that specify which users are allowed and not allowed to run cron jobs
/etc/cron.allow and /etc/cron.deny
Default is a blank cron.allow to allow all users to run cron jobs.
Path to files that specify users who are allowed or not allowed to run batch jobs.
/etc/at.allow and /etc/at.deny
If at.allow exists, only those users specified can use at.
Path to centralized location to manage crontabs named by username on servers with many users.
/etc/cron.d/
Path where individual user crontabs are stored.
/var/spool/cron/*
Path where anacrontab stores job identifiers like cron.daily, cron.weekly, and cron.monthly.
/var/spool/anacron/*
Path to the cron daemon.
/usr/sbin/crond
Path to the shell used to execute cron jobs.
/usr/bin/sh
Method for editing anacrontab.
vi /etc/anacrontab
If an empty /etc/cron.deny exists and no /etc/cron.allow exists, can users still use the crontab command?
Yes
