Cron jobs in Ubuntu - cron

How to run a cron job in ubuntu in such a way that it should initiate a python script?
Please explain with a small example.

You can set a simple line to run from x to x time:
e.g.,
0,10,20,30,40,50 * * * * ~/py/my_python_script.py
runs every 10 minuts
STEP BY STEP USING VIM AS THE SELECTED EDITOR
At your terminal, run: sudo crontab -e
Afterwards, choose you favorite editor (e.g., vim)
type :i and hit enter to insert a new line
Past or write the cronjob line 0,10,20,30,40,50 * * * * ~/py/my_python_script.py and hit enter and then return to exit that line
type :w and hit enter, to write the file
type :q and hit enter to exit
Description for the asterisks:
minute (0-59), hour (0-23, 0 = midnight), day (1-31), month (1-12), weekday (0-6, 0 = Sunday), command
In-deep:
To read a more detailed process on how it all works:
CronHowto
VIM Commands Cheat Sheet

You can run Crontab in Ubuntu.
Simply just copy and paste the following script in the terminal.
crontab -e
There you can write command for run your python script, that will execute the program in a specific time interval.
* * * * * python </path/to/the/file>
You can refer the link for the time interval
You can check the log file here
tail -f /var/log/syslog

Related

How to run a .py file using Crontab in Terminal?

I have a python code which must run every hour.
I set Crontab to be:
0 * * * * python /Users.../file.py
Will it actually run the python code? Or Crontab can only do things like 'echo' etc?
Yes, you can run the python code from Crontab here is an example that I use:
First, to open crontab file:
crontab -e
On the last line of crontab file I write the command:
0 */4 * * * python3 /home/integrations/geckoboard/diario1.0.py
Where integrations is my User, geckoboard my folder and diario1.0.py is the code I want to run
With that my pythonfile will run every 4 hours.

Crontab absolute path not working

I have a script to backup my database at /home/<user>/bin/dbbackup. The script is executable by all users, and owned by me. The files /etc/cron.allow and /etc/cron.deny do not exist.
In my crontab I have the following lines (including a new blank line after the last line of code):
#reboot /home/<user>/.dropbox-dist/dropboxd
30 2 * * * bash /home/<user>/bin/dbbackup
However, cron is not running my dbbackup script. When I run a manual test of the script it works. When I run this test on the command line: * * * * * /bin/echo "cron works" >> ~/file I get the following error:
No command 'dbbackup' found, did you mean:
Command 'dvbackup' from package 'dvbackup' (universe)
Command 'tdbbackup' from package 'tdb-tools' (main)
dbbackup: command not found
My server is running Ubuntu Trusty. Any help please?
As the comments noted, it appears that amiga_os needed remove the reference to bash in the line.
30 2 * * * bash /home/<user>/bin/dbbackup
Should be.
30 2 * * * /home/<user>/bin/dbbackup
I usually just call scripts from their path and use "#!/bin/bash" (or wherever your bash lives) as the first line of the script. It appears the amiga_os had already done this, which is good. I don't like putting sentences into cron because it makes me nervous.
I think it was a path issue as cron executes as the user but does not read the bash profile and therefore does not work exactly like it would under your shell as it might not have access to your $PATH.

Linux .SH Programs

I just like to ask if anyone here knows how to automatically start a .sh program in Linux on a daily basis.
This is because I have a server running which runs untill a certain point at midnight then stops. I'd like to have a program that can automatically restart it at a certain time every day.
you can automatically run the script by using the cron deamon
First you have to add the command to cron
crontab -e //this will open a file with your default editor
//to this file add your command at last
command syntax:
* * * * * * /home/loc/shell.sh //runs every minuite
ex */45**** /home/loc/shllscript.sh // runs every 45 mins
cron will do what you need to do.
The first line will start your script at 2:30 every day. The second line will stop it at 12:00
30 2 * * * myscript.sh
00 12 * * * killall myscript.sh
you can also refer to "at", which can run jobs at certain time period

Confusion about Crons

this is my first time writing script for cron job.
I wrote my code in shell, (which it works) and I'm trying to set it up for cron.
So here is my question. How do I set up the cron? Am I suppose to write
10 * * * * /home/workstation/deleter.sh (I want it to run every 10min)
right underneath #!/bin/sh? How would I execute it? (deleter.sh has permission via chmod)
man 1 crontab returns "No entry for crontab in section 1 of the manual"
I'm really lost and confused right now. If someone know how to set up cron please tell me!!
Thanks in advance
#!/bin/sh
counter=0
logloc=/home/ServerLogs
backup=/home/test
## Reads the location of the file systems that needs to be investigated from location.txt
## and save it into an array
while read -r line; do
Unix_Array[${counter}]=$line;
let counter=counter+1;
done < location.txt
## Reads Email recipients and save it into an array
More code continues from here......
The following will open your environment's text editor and load the crontab:
crontab -e
Your crontab entry is mostly correct. In order for your script to run every ten minutes it should be changed to:
*/10 * * * * /home/workstation/deleter.sh
The entry you indicated would run the script at the 10th minute of every hour.
To setup the cron, you can do one of two (main) things. The first would be to place the specified line in /etc/crontab. The second would be to run crontab -e and place the line in there. I would recommend to use crontab -e so the cron will execute as your own user account.
If the full path to the script is /home/workstation/deleter.sh and it does have execute-privileges, as you specified - your current line will have it execute 10-minutes past the hour, every hour. To get it to execute every 10 minutes, you'll have to use */10, like this:
*/10 * * * * /home/workstation/deleter.sh
this might help
http://www.manpagez.com/man/5/crontab/
you need to get an entry into your crontab
One of the best links I came across when I first learned about cron! Bookmark it
http://www.thegeekstuff.com/2009/06/15-practical-crontab-examples/

crontab doesnt work in linux

My Linux version is red hat enterprise linux server release 5.3 tikanga
i have schedule crontab as below
1 * * * * /usr/testjob.sh 2>&1 >> /usr/result.txt
crontab job not running on scheduled time...
Please suggest..
Try this at first.
* * * * * /usr/testjob.sh
Then you may received a mail for every minutes. Check the error output.
Sometimes, it may caused by your default shell is just sh instead of bash.
So, maybe ">>" is not supported.
You should check do you have /usr permission when you want to write into it.
As said by +Shawn Chin, if you want to run your command only once, the at command is your friend.
If you want to run your command repeatedly, then you are right to use the cron framework. The manual page explaining the fields of the crontab may be obtained with the following command:
$ man -s 5 crontab
You appear to be in an Indian time-zone (IST). You may have to specify that into the crontab. For instance, using the 'crontab -e' command (to save and quit, type 'ESC-wq', as the editor is VI by default):
#
CRON_TZ=IST
# run at 06:33 (am), every day
33 06 * * * /usr/testjob.sh >> /usr/result.txt 2>&1
Note that '2>&1' should be placed AFTER '>> /usr/result.txt', not before.
just to mention it and make sure
NOTE: Each cron table entry must have a trailing line break in order
for the cron table entry to be recognized.

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