1. Install Crontab in Batch Mode
By specifying the file name as an argument to crontab command, you can install the new cron jobs from a text file as shown below.
First create a text file with all your cron job entries.
$ cat cron-file.txt * * * * * /bin/date >> /tmp/date-out * * * * * /bin/ls >> /tmp/ls-out
Next, install the cron jobs from a text file as shown below.
$ crontab cron-file.txt
Note: This will overwrite the existing cron entries.
2. Edit crontab in Batch Mode
You can edit the crontab in batch mode using various methods (for example, using sed).
Example: Change output redirection from write to append for all cron jobs.
$ crontab -l * * * * * /bin/date > /tmp/date-out * * * * * /bin/ls > /tmp/ls-out $ crontab -l | sed 's/>/>>/' | crontab - $ crontab -l * * * * * /bin/date >> /tmp/date-out * * * * * /bin/ls >> /tmp/ls-out
3. Remove All cron jobs of the Current User
Crontab’s -r option removes all cron job for the current user. If you have appropriate privilege, you can even remove other user’s cron jobs using the -r option along with the -u user option.
Example: Remove the current user cron entries.
$ crontab -r
Example: Remove the specified user cron entries.
$ crontab -r -u USERNAME
