procmail -- The procmail mail processing program.<hr>
<a href="http://www.procmail.org">http://www.procmail.org</a><hr>
The procmail program is used by CentOS for all local mail delivery. In
addition to just delivering mail, procmail can be used for automatic
filtering, presorting, and other mail handling jobs.  Procmail is also
the basis for the SmartList mailing list processor.
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