If - for example - cron jobs output to stdout, which is the process collecting the output and writing to these directories ?

/var/spool/clientmqueue /var/spool/mqueue /var/spool/mail

Where can I find docs on the inner details (pipe, rpc, ...) of the "redirection" from stdout to mail files ?

If I send an email whith sendmail, does it do the same routing as above ? docs ?

  • If you run any mta process than it will write the mailboxes. Sep 16, 2018 at 9:48

1 Answer 1


I rename the sendmail true executable


and replaced it with this bash script :


date >> $LOGFILE
cat /proc/$PPID/cmdline | tr '\0' ' ' >> $LOGFILE
echo >> $LOGFILE
echo $* >> $LOGFILE

The first fish caught in the net is CROND

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