What is centos crontab?

[CentOS-DollarUser]

What is centos crontab? I am about to install centos on my computer. I was just going through the features and i came acros this thing crontab. What is it? What does it do? Just a curious noob. So please help...

[Baker]

Cron is a time-based job scheduler in Unix-like computer operating systems. 'cron' is short for 'chronograph'. Cron enables users to schedule jobs (commands or shell scripts) to run automatically at a certain time or date. It is commonly used to perform system maintenance or administration, though its general purpose nature means that it can be used for other purposes, such as connecting to the Internet and downloading email...

[Devasis]

The default contents of the main config file of crontab contains the following content :

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

Crontab is basically used for scheduling programs or applications to run at a specific time similar to windows task scheduler. Hope this helps you...

[Solomon]

Example of crontab's usage :

# record the memory usage of the system every monday 
# at 3:30AM in the file /tmp/meminfo
30 3 * * mon cat /proc/meminfo >> /tmp/meminfo
# run custom script the first day of every month at 4:10AM
10 4 1 * * /root/scripts/backup.sh

For complete detail visit redhat's official site. CentOS is derived from redhat so no issues of changes in feature. See the complete documentation : http://www.redhat.com/docs/manuals/l...cron-task.html