Crontab definition: 

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The daemon which reads the crontab and executes the commands at the right time is called cron, named after Kronos, the Greek god of time.

I have frequently 'croned' and 'uncroned' jobs, meaning I simply worked on the crontab file directly to schedule new jobs, change the execution time setup, retrieve jobs that were no longer necessary or temporarily suspend scripts.

How to do that? By using the crontab command line to open, edit the crontab file, modify and save it as needed.

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Syntax:
crontab [-u username] filename
crontab [-u username] [-l|-r|-e] [-i] [-s]
 

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---- crontab -e
to EDIT the cron table

Once in it, ESC, forward slash to mk a search in it, type the text we look for, ENTER

type 'n' to go to next occurrence

​​type 'i' to insert

To save and exit: ESC, colon(:), type "wq" to write (save) and quit the crontab, and then ENTER

To exit without saving: ESC, :q!, ENTER

Another option to search if ESC \ does not work is to do / and type what you are searching then ENTER

n to go to next occurrence etc

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---- crontab -l
display the current crontab

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---- crontab -r
remove the current crontab /!\

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---- crontab -i
Also remove the crontab but prompt a yes/no question before
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---- crontab -u username
Specifies the user whose crontab is to be viewed or modified.
If this option is not given, crontab opens the crontab of the user
who ran crontab. Note: using su to switch users can confuse crontab,
so if you are running it inside of su, always use the -u option
to avoid ambiguity.

 

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