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I am automatically running a simple python program from start up using cron. The pi boots / automatically logs in, displays the command line and runs the python program but the print output (updating count) is not displayed.

The print output works fine if I run the program via idle (ie having enabled LXDE) and it also works fine if (without running the LXDE desktop) I manually run the program from the command line, e.g. sudo python pimon.py

What is needed to see the print output when I start the program using cron? I do not want to have to enable the LXDE desktop first.

The crontab entry is: @reboot python /home/pi/Python27/pimon.py

share|improve this question
    
Please show your crontab entry. – mazianni Apr 2 '15 at 17:26
3  
Your script run by cron simply has no console to print its output too. The behaviour you describe is perfectly normal. Best way to work around: make your script output to a file. – Ghanima♦ Apr 2 '15 at 17:29
1  
Where have you told the output to go? A cron job is not started from a terminal so is not attached to a keyboard or screen. Perhaps you need to redirect the output to a file. – joan Apr 2 '15 at 17:29
    
See also: raspberrypi.stackexchange.com/questions/40493/… – Ghanima♦ Jan 6 at 0:25
up vote 4 down vote

As others have noted in the comments, you need to redirect the output from the command somewhere.

This will write to a file, overwriting the file if it already exists.

@reboot python /home/pi/Python27/pimon.py > /path/to/output_file.txt

Change > to >> if you want to append to an existing file.

Check this link for more information on standard input and output redirection.

share|improve this answer
    
Please note that the ampersand is not necessary since cron already forks the program. – Ghanima♦ Apr 3 '15 at 19:57

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