[SOLVED] Help me figure out this cronjob syntax

tuxthegreat · 07-20-2021, 05:04 AM

I want to make a backup of kodi once a week, let's say Tuesday @ 12:10pm here is what I have so far

Code:

10 12 * * 2 tar -czf kodi-bakup.tar.gz ~/.kodi /home/odroid/kodibackup >/dev/null 2>&1

But it's not doing the cronjob, no output in syslog either just this little output

Code:

Jul 20 11:45:24 odroid crontab[10775]: (root) REPLACE (root)
Jul 20 11:45:24 odroid crontab[10775]: (root) END EDIT (root)
Jul 20 11:46:01 odroid cron[758]: (root) RELOAD (crontabs/root)
Jul 20 11:46:01 odroid CRON[10847]: (root) CMD (tar -czf kodi-bakup.tar.gz ~/.kodi /home/odroid/kodibackup >/dev/null 2>&1)
Jul 20 11:46:52 odroid crontab[10863]: (root) LIST (root)

What am I doing wrong guys ?

Update: It seems that my mistake was using sudo -s and then crontab -e, when I did it without sudo permission it worked. But not completely, I am still unable to save it in /home/odroid/kodibackup , instead it saves it to /home/odroid. Also how can I make it so that when first one is done, the second one will show up as kodi-bakup.tar.gz.1, kodi-bakup.tar.gz.2. and so forth.

petelq · 07-20-2021, 07:34 AM

I find that with a slightly more complex instruction, it's better to compile a bash script and run the script in crontab.

jmgibson1981 · 07-20-2021, 10:14 AM

Indeed. The other benefit is with a script you can test it, not wait for cron to run and fine out then. The script can be activated endlessly as you adjust and tinker. Of course the same could be said that you can make the script, then just copy the line into the crontab I suppose once it works. Don't forget about potential PATH issues though. Cron doesn't have the normal PATH by default.

Looking at your entry that may be the issue actually.... PATH isn't set. Try full path to tar.

TB0ne · 07-20-2021, 10:48 AM

Quote:

Originally Posted by AliceWhorton

Thanks for sharing your thoughts!

What did you think was best here? I agree with petelq and jmgibson1981, about putting the complex statements in a script and executing it. What would you have done??

TB0ne · 07-20-2021, 11:11 AM

Quote:

Originally Posted by AliceWhorton

Now i guess that i am going to do as jmgibson1981 said, i just can't find any other solution, maybe you can share some new advice???

Perhaps if you opened your own thread, and provided your own details and asked your own question, we can. You just thanked folks for 'sharing their thoughts'....I asked what, in particular, you found helpful.

tuxthegreat · 07-20-2021, 04:07 PM

Ok guys calm down, were all friends here

OK I like this script idea, it's clean and can be adjusted to my liking, only problem is I don't know how to write a script.

But I don't want to give up, I can try to do this with your help. Let's see what I want done, first task is this

Code:

tar -czf kodi-bakup.tar.gz ~/.kodi

then I want to put the resulting tar.gz package into a directory here

Code:

/home/odroid/kodibackup

and third I want this to happen once a week, anytime really, my server runs 24/7. So what can we do guys, let's put on our thinking caps on.

jmgibson1981 · 07-20-2021, 04:38 PM

You can do it in one shot. I'm not very familiar with tar admittedly. You must have permissions to write to the location.

Code:

tar -czf /home/odroid/kodibackup/kodi-backup.tar.gz ~/.kodi

tuxthegreat · 07-20-2021, 04:55 PM

Quote:

Originally Posted by jmgibson1981

You can do it in one shot. I'm not very familiar with tar admittedly. You must have permissions to write to the location.

Code:

tar -czf /home/odroid/kodibackup/kodi-backup.tar.gz ~/.kodi

Thank you, your method worked, all I had to do was chmod 777 the dir in question and everything works great now. Thank you again.

TB0ne · 07-20-2021, 05:32 PM

Quote:

Originally Posted by tuxthegreat

Ok guys calm down, were all friends here

OK I like this script idea, it's clean and can be adjusted to my liking, only problem is I don't know how to write a script.

Sure you do...a script, in its most basic form, is just a list of commands you can type in on the command line. Put them in a file, and make the file executable (chmod 755 <filename>).

So your tar command, and whatever else you want can go into "/path/to/your/filename". That's it...the commands in that file will run one by one. If they run on the command line, they'll run in the script. An important note, though, for both scripting and cron jobs...specify the full paths to executables. Don't just put 'tar', put "/usr/bin/tar", and the like.

Granted, scripts can have loops, variables, etc., etc., but in your case, you just want one command.

Quote:

But I don't want to give up, I can try to do this with your help. Let's see what I want done, first task is this

Code:

tar -czf kodi-bakup.tar.gz ~/.kodi

then I want to put the resulting tar.gz package into a directory here

Code:

/home/odroid/kodibackup

and third I want this to happen once a week, anytime really, my server runs 24/7. So what can we do guys, let's put on our thinking caps on.

Have you checked any of the MANY thousands of bash tutorials, since you say you can't write a script?? There's even one in my posting signature...write your script, and put it in cron.

Lots of cron examples and tutorials...have you referenced any?? Simple cron explanation:

Code:

cron field explanation...suitable for inclusion in your crontab file
# *     *     *   *    *        command to be executed
# -     -     -   -    -
# |     |     |   |    |
# |     |     |   |    +----- day of week (0 - 6) (Sunday=0)
# |     |     |   +------- month (1 - 12)
# |     |     +--------- day of        month (1 - 31)
# |     +----------- hour (0 - 23)
# +------------- min (0 - 59)

tuxthegreat · 07-20-2021, 07:13 PM

Quote:

Originally Posted by TB0ne

Sure you do...a script, in its most basic form, is just a list of commands you can type in on the command line. Put them in a file, and make the file executable (chmod 755 <filename>).

So your tar command, and whatever else you want can go into "/path/to/your/filename". That's it...the commands in that file will run one by one. If they run on the command line, they'll run in the script. An important note, though, for both scripting and cron jobs...specify the full paths to executables. Don't just put 'tar', put "/usr/bin/tar", and the like.

Granted, scripts can have loops, variables, etc., etc., but in your case, you just want one command.

Have you checked any of the MANY thousands of bash tutorials, since you say you can't write a script?? There's even one in my posting signature...write your script, and put it in cron.

Lots of cron examples and tutorials...have you referenced any?? Simple cron explanation:

Code:

cron field explanation...suitable for inclusion in your crontab file
# *     *     *   *    *        command to be executed
# -     -     -   -    -
# |     |     |   |    |
# |     |     |   |    +----- day of week (0 - 6) (Sunday=0)
# |     |     |   +------- month (1 - 12)
# |     |     +--------- day of        month (1 - 31)
# |     +----------- hour (0 - 23)
# +------------- min (0 - 59)

The link on your bash is causing a "The page isn’t redirecting properly"

TB0ne · 07-21-2021, 07:28 AM

Quote:

Originally Posted by tuxthegreat

The link on your bash is causing a "The page isn’t redirecting properly"

Works for me; many others can be found as well, this is one of the better ones:
https://tldp.org/LDP/Bash-Beginners-Guide/html/

TB0ne · 07-21-2021, 07:28 AM

Quote:

Originally Posted by AliceWhorton

Same for me

No, sorry...you just wanted to update your post with your spam essay-writing site. Reported.