问题
I have a PHP script that sends out a bi-weekly reminder to subscribers. Each time it sends out the email it also sends out an email that comes in from "Cron Daemon." When I first wrote the script, it didn't send this email, but now it does. I have a few questions about this.
This is what the email says:
Set-Cookie: PHPSESSID=((random letters and numbers here)); path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Content-type: text/html
- What does this email mean?
- Why is this email being sent?
- Is there a way to stop the scrip from sending this email?
回答1:
Cron reads the stdout/stderr of the command that gets executed, if something is written then cron sends an E-Mail.
I guess the php-executable is compiled as "cgi" or "fcgi" so it emits those headers by default.
To solve this you have apparently three possible solutions:
- Use the "cli" version of PHP
- Redirect stderr and stdout to /dev/null (that means append
> /dev/null 2>&1to your cron command). - Define
MAILTO=""(see this page).
回答2:
My guess is your PHP script is rendering something to the output. If anything gets rendered at all, cron forwards that to the default administrator email.
There's two solutions to this:
1) Fix your PHP script to not output anything at all. This is sometimes harder than it would seem, especially for non-trivial scripts.
2) Prevent the cron script from ever having an output. The drawback to this method is you won't get a notice when the script fails, either. To stop the output, use something like this:
#Before
* * * * * php /path/to/script
#After
* * * * * php /path/to/script > /dev/null 2>&1
来源：https://stackoverflow.com/questions/6952082/extra-email-from-cron-daemon-when-running-an-email-list-script