问题
I have a cron job and its output is now redirected into a file. It looks like the following
0 9 * * * /bin/sh /bin/cleanup.sh > /home/darkknight/cleanup.log
Can any one help me to rediect its output to stdout?
回答1:
Enter tty on any terminal and we will get device file for that particular teminal window like /dev/pts/1. Redirct the cron job into this file as
cleanup.sh > /dev/pts/1
回答2:
Running process has a PID and its fd (file descriptor) is mapping to /proc/<PID>/fd. And we can find PID of the running cron process at /var/run/crond.pid.
To send cron log to stdout, we could write log to fd number 1 of the process started by cron.
0 9 * * * /bin/sh /bin/cleanup.sh > /proc/$(cat /var/run/crond.pid)/fd/1 2>&1
回答3:
Run cat /home/darkknight/cleanup.log then you get the output on STDOUT.
If you can't see what you expect as output, maybe you need to modify the cron as following:
0 9 * * * /bin/sh /bin/cleanup.sh > /home/darkknight/cleanup.log 2>&1
To get what cleanup.sh writes on its STDERR.
If you don't want to lose the output of yesterday, modify as following:
0 9 * * * /bin/sh /bin/cleanup.sh >> /home/darkknight/cleanup.log 2>&1
Or, just execute /bin/sh /bin/cleanup.sh then you get both STDOUT and STDERR on your terminal.
来源：https://stackoverflow.com/questions/36441312/how-to-redirect-cron-job-output-to-stdout