To add a cron task item using a script, you can utilize the following script:
#!/bin/bash
# Define the crontab entry
CRONTAB_ENTRY="* * * * * echo \"hello, world!\" >> log_.txt 2>&1"
# Write the crontab entry to a temporary file
echo "$CRONTAB_ENTRY" > /tmp/my_cron
# Load the temporary crontab file
crontab /tmp/my_cron
# Remove the temporary file
rm /tmp/my_cron
Please note that running the above script will reset the crontab list, removing all previous items.
If you wish to create a log file for each day, you can replace the line:
CRONTAB_ENTRY="* * * * * echo \"hello, world!\" >> log_.txt 2>&1"
with:
CRONTAB_ENTRY="* * * * * echo \"hello, world!\" >> log_\$(date +\%Y\%m\%d).txt 2>&1"
Take note of how the Linux command is included within the crontask item above.
To view the current cron task list, you can use the command:
$ crontab -l
* * * * * echo "hello, world!" >> log_$(date +\%Y\%m\%d).txt 2>&1
CRONTAB_ENTRY="* * * * * echo \"hello, world!\" >> log_\$(date +\%Y\%m\%d).txt 2>&1"
Note that the slash before the dollar sign is essential in this command. If the slash is removed:
CRONTAB_ENTRY="* * * * * echo \"hello, world!\" >> log_$(date +\%Y\%m\%d).txt 2>&1"
The updated cron task list will appear as:
$ crontab -l
* * * * * echo "hello, world!" >> log_20230711.txt 2>&1
The cron task list is crucial for scheduling and automating tasks on a system. It is important to ensure the correct syntax and formatting in the cron task list to ensure proper execution and logging of tasks.