Not all cron jobs are created equal, and some of them can afford to fail sporadically before we need to worry about them. Maybe they rely on a third party server, and we don’t want the occasional fail to pollute our inbox.
Here is a little cron job wrapper I created that will suppress stderr but keeps track of the job’s returned exit codes. Above a certain threshold of consecutive abnormal exits it doesn’t suppress stderr anymore.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | # if the counter file doesn't already exist we create/initialize itif [ ! -f /tmp/counter_ri7g3 ] ;then echo 0 > /tmp/counter_ri7g3 ;fi ;# we pull the current countercounter=`cat /tmp/counter_ri7g3` ;# if the counter is still small, we send stderr to /dev/nullif [ $counter -lt 5 ] ;then $1 > /dev/null 2>&1 ;# otherwise stderr will follow its normal path and find its way to emailelse $1 > /dev/null ;fi ;# lastly if running the $1 resulted in an abnormal exit, the counter is incrementedif [ ! $? = 0 ] ;then counter=`cat /tmp/counter_ri7g3` ; echo "$counter+1" | bc > /tmp/counter_ri7g3 ;# and if $1 exited normally, we reset the counterelse echo 0 > /tmp/counter_ri7g3 ;fi ; |
a cron entry calling it looks as such:
1 | 30 * * * * root /usr/local/bin/cron_wrapper "/path/to/script arg_1 arg_2" |