SHELL

how to edit crontab in linux

Step 1 : crontab -e
Step 2 : Select your prefered editor for the file.
Steo 3 : Add the command that you want to execute from cron and save that file.
		Example : 1 0 * * 0 rm /home/jones/*.log > /dev/null 2>&1
Step 4 : check if cron is activate using command
		crontab -l

edit crontab daily

crontab -e
@monthly root /usr/bin/ntpdate > /dev/null 2>&1
service crond restart

change crontab editor

#run command in terminal:
select-editor

#Then select an option:
Select an editor.  To change later, run 'select-editor'.
  1. /bin/nano        <---- easiest
  2. /usr/bin/vim.tiny
  3. /bin/ed

Choose 1-3 [1]:

crontab edit

crontab -e		# open user crontab in edit mode
i      			# for insert.  Make your changes
:wq!   			# quit and save
crontab -l		# open user crontab in read mode

edit crontab daily

grep -R cron /etc

edit crontab daily

Newer versions use /etc/anacrontab. By default, cron.daily scripts are run at 4:02. Editing /etc/crontab will modify that time.

# 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