What is preventing my cron job from running

Question

I have created a list of cron jobs (see below) using sudo crontab -e in the root crontab file. When I run the commands individually on the command line, they work fine, however none of the jobs are run by cron. Any help would be appreciated. Do I need to add something else into the crontab file?

48 * * * * sudo gzip -k /calcservergc.log.*

49 * * * * for file in /calcservergc.log.*.gz; do sudo mv $file $(hostname).${file:1}; done

50 * * * * sudo rm $(hostname). .log. .gz

Answer 1

sudo

The sudo command may not work in a crontab. Generally you need a password to run sudo but there might be a way to have it run without a password when running in a cron job. This would not be recommended however to attempt.

cron

You'll need to run the cron as a user that has access to do what you need to accomplish. Cron runs with a short list of specific paths. By default that list is pretty short. On a linux box I use the path is /sbin:/usr/sbin:/bin:/usr/bin .

Also, the paths need to be more specific. Cron doesn't run as a normal user so you have to be more specific with paths and output of those commands.

For instance, on the first command, where will the gzip file be placed?

logrotate

It looks like you're trying to zip a log file, then move log files, then remove old log files - this is exactly what logrotate accomplishes. It would be worth installing. Logrotate solves problems like the log file being opened when you run this command - generally the process that has the log file opened doesn't lose the file handle even if you rename it so the log continues to be written to even after you move it. It also handles the problem of keeping an archive of the recent log files, like syslog.1.gz, syslog.2.gz, syslog.x.gz or as many back as you have storage space for or want to keep for posterity.

Summary

• Don't use sudo in cron
• Be specific in paths when running commands in cron
• Use logrotate to accomplish this specific task in your question

Answer 2

I don't have 50 points of reputation so can't comment on your question, so I'll try to say it in one shot.

I detect a possible problem with your 3 commands each called at one minute apparts. Let's say the first operation takes more than one minute to run (shouldn't happen but in theory it could), your second call won't work or worst, it could work on half the data). You don't want to loose time by, lets say, put 5 minutes delay between your commands, that would be a lost of time.

What you could do is create a shell script in which you put the 3 commands. This way it will prevent your operations to "crash". So just put your 3 commands in a script shell and they will be executed one after the other.

Then put your file in a place like /bin (you can also create a symbolic link with ln -s) and call your script with cron. (Be careful with the paths in the script shell)

Now, for the sudo problem ... well even if you put it in a shell script, you would still need to pass your sudo password, and cron runs in the background so you won't be able to enter your password.

You could try two solutions. Change the rights on the containing folder where your files are stored (by using chmod -r 777 or chmod 755 on the folder) or move/copy your files in a directory where you have access to read and write.