How can I check if crontab has successfully run in Linux?

To check if the crontab has been executed successfully, you can use the following method:

1. You can check the /var/log/syslog or /var/log/cron log files, which record the execution logs of system and cron tasks. You can use the following command to view the execution status of cron tasks:

grep CRON /var/log/syslog

Or

grep CRON /var/log/cron

The execution results will display the status of the cron tasks, including the execution time, command, and outcome.

1. Redirect the output of a cron job to a file to determine if the task was successfully executed. For example, redirect the output of the task to the file /tmp/output.log.

* * * * * /path/to/command >> /tmp/output.log 2>&1

Then use the cat command to view the output file:

cat /tmp/output.log

If the output file contains the expected output content, it indicates that the task has been successfully executed.

1. One option is to add logging functionality in the cron job to write the execution status to a custom log file. For example, you can write the execution status of the task to the file /var/log/crontab.log.

* * * * * /path/to/command >> /var/log/crontab.log 2>&1

Then use the cat command to view the log file:

cat /var/log/crontab.log

If there are records of task execution in the log file, it indicates that the task has been successfully executed.

Please note that the above method is applicable to Debian-based Linux distributions such as Ubuntu and Debian. For other Linux distributions, the path and name of the log file may vary.