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3.1 micrond Invocation

The micrond daemon takes no command line arguments. Its behavior is controlled by command line options.

Unless instructed otherwise, upon startup micrond disconnects from the controlling terminal and remains in the background. During normal execution it logs its diagnostic messages (if any) via syslog facility ‘cron’. Eventual output and error diagnostics from the invoked cron jobs are mailed to the job owner, as described in Mailing the cronjob output.

The following options modify the micrond behavior:


Remain in foreground.


Display a short help summary and exit.

-g group=dir

Define the directory or file name for crontab group group. Valid group names are: master, system, user, and group. See Crongroups.

-g group
-g nogroup

Enable or disable crontab group group. Note, that the group crontab group is disabled by default.

-l pri

Log only messages with syslog priority pri or higher. Valid arguments are, in order of increasing priority: debug, info, notice, warning, err, crit, alert, and emerg.

-m mailer

Set the mailer command. Default is /usr/sbin/sendmail -oi -t.

-P file

Write PID of the program to file.

-p socket

Send messages to syslog via this socket. The argument is either an absolute file name of a UNIX socket, or a host name or IPv4 address optionally followed by a colon and port number or service name.


When running in foreground (see the -f option), log messages from micrond to the syslog facility ‘cron’, instead of printing them to the standard error. Not to be confused with the -s option, described below.


Log output from cronjobs to syslog. By default, the ‘cron’ facility is used. Use the -v syslog_facility=f option to change it to facility f. See below, for the discussion of the -v option.

-T N

In foreground mode, when logs go to stderr, precede each line with a timestamp in ISO 8601 format (-T0). N can be 1 to skip seconds and 2 to skip both minutes and seconds from the timestamp.

-t n

Before exiting, micrond checks if any of the cronjobs are still running. If so, it sends them the SIGTERM signal and waits n seconds for them to terminate. The cronjobs that fail to exit within that amount of time are terminated forcibly by sending them the SIGKILL signal.

The default timeout is 60 seconds.


Print program version, licensing information and exit.

-v name=value

Assigns initial value for the micrond internal variable name (see built-in variables). The variable name must be used without prefix. Comparison is case-insensitive. For example:

-v syslog_facility=daemon

is equivalent to

-W opt

Set internal micrond option. As of version 1.3.93, only one such option is implemented: paranoid_memfree. When -Wparanoid_memfree is given, micrond will meticulously free all allocated memory before terminating. Normally this isn’t needed, as the operating system will reclaim that memory anyway. Use this option if you run micrond under valgrind or another memory leak detector, in order to avoid spurious warnings.

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