crontab fails to write logs
By Emma Martinez •
I'm using crontab to run a python script every minute. This is my how my crontab file looks like:
*/1 * * * * source /root/.bashrc && source /home/env/bin/activate && python /home/manage.py shell < /home/script.py >> /var/log/navjob.log 2>&1When try to check cron output in syslog with this command #grep CRON /var/log/syslog the output is like this:
...CRON[764888]: (root) CMD (source /root/.bashrc && source /home/env/bin/activate && python /home/manage.py shell < /home/script.py >> /var/log/navjob.log 2>&1)
...CRON[764887]: (CRON) info (No MTA installed, discarding output)But the log file (/var/log/navjob.log) is empty and the code is not run!
1 Answer
When you chain commands and add redirection like
cmd1 && cmd2 && cmd3 >> somefile 2>&1(or cmd1 ; cmd2 ; cmd3 >> somefile 2>&1 etc.) the redirections only apply to the last command in the chain. To redirect all of them, you need to group the commands like
{ cmd1 && cmd2 && cmd3 ; } >> somefile 2>&1or (with a subshell)
( cmd1 && cmd2 && cmd3 ) >> somefile 2>&1In this case, your cron job is likely failing at the very first source command, since source is a bashism and cron's default shell is /bin/sh - either add SHELL=/bin/bash before the crontab entry, or change source to the POSIX .
