问题
I'm writing files out to a log ran by a bash script using cron. The call on cron looks like this:
*/25 * * * * bash script.sh > "/var/log/$(date +%Y-%m-%d_%H:%M).log"
But when I check the crontab it records as
*/25 * * * * bash script.sh > "/var/log/$(date +).log"
And it never writes the log file. Is there something I need to change to get cron to write the date?
回答1:
It is a matter of escaping variables:
* * * * * /usr/bin/touch /tmp/$(date +\%Y:\%m).log
# ^ ^
worked to me.
From man 5 crontab:
Percent-signs (%) in the command, unless escaped with backslash (\), will be changed into newline characters, and all data after the first % will be sent to the command as standard input.
So
*/25 * * * * /bin/bash script.sh > "/var/log/$(date +\%Y-\%m-\%d_\%H:\%M).log"
# ^ ^ ^ ^ ^
should work.
Note I used /bin/bash instead of just bash.
来源：https://stackoverflow.com/questions/16238460/why-percent-signs-do-not-work-in-crontab