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3 micrond

micrond executes commands periodically as directed by one or more crontabs. See Crontabs, for a discussion of crontab locations and format.

Normally, a cron job is not run if its previous instance is still running. For instance, if a cron job scheduled to run each minute takes three minutes to finish, it will be actually run once in three minutes. This behavior can be altered by setting the _MICRON_MAXINSTANCES variable to the desired number of cron job instances that can be run simultaneously (use _JOB_MAXINSTANCES to change the setting for one job only, see _MICRON_MAXINSTANCES).

Depending on the cronjob settings, any data the running job produces on its standard output and standard error can be logged via syslog in real time, or captured and, upon termination of the job, mailed to the job owner or appended to a file (see Cronjob Output).

On GNU/Linux systems, micrond monitors each opened crontab for modifications and re-reads it as soon as it is written to disk. On other systems, it checks crontab modification times each minute and re-reads those crontabs for which this value has changed.