mjhjmtu

I have this cronjob:

#!/bin/bash
YEAR=`date +%Y`
MONTH=`date +%m`
DAY=`date +%d`
mkdir -p $YEAR/$MONTH/$DAY
mysqldump -uroot -p1234 locatari > $YEAR/$MONTH/$DAY/backup.sql

And I want to run this at each let's say 3 minutes. I tried with each of these crontab commands and none on them seems to work:

3 * * * * /usr/bin /home/rome/cronjob/back.sh > /home/rome/cronjob
3 * * * * /home/rome/cronjob/back.sh/
3 * * * * exec `/bin/bash /home/rome/cronjob/back.sh`
3 * * * * /bin/bash /home/rome/cronjob/back.sh > /dev/null 2>&1

I only made it run when I did:

bash back.sh

All worked as expected with the bash command, what is wrong to my cron scheduler? Problem is that with the crontab command, I can't see my output, it only works with bash command.

None of your crontab job entries matches what you typed at the command line

1. 
   /usr/bin /home/rome/cronjob/back.sh tries to run a program /usr/bin, but that's a directory


2. 
   /home/rome/cronjob/back.sh/ tries to treat your script as a directory


3. 
   exec `/bin/bash /home/rome/cronjob/back.sh` tries to use the output of your program as a program name to run


4. 
   /bin/bash /home/rome/cronjob/back.sh > /dev/null 2>&1 this might work, except that you have thrown away all the output of the script, so you won't see any errors

Based on feedback from your comments it seems you probably want something like this (I've omitted /home/rome because that is your home directory anyway):

*/3 * * * * cd cronjob && bash back.sh >back.log 2>&1

Your cron schedule expression means "At every minute 3" => each hour.

Every 3 minutes would be:

*/3 * * * *

See this nice tool to check the expression.

Also only your last cron command will work. But I would not redirect the output to /dev/null. If there are any problems with your script, it's difficult to debug.