Growl Notification Output Plugin First, you must set up growl can "Listen for incoming notifications" at "Growl" in "System Preferences". fluent.conf example: ===== <match growl.**> type growl server localhost #password fluent appname Fluent Growl Notify <notify> name Notify priority 0 sticky false </notify> <notify> name StickyNotify priority 0 sticky true </notify> </match> ===== and some command line example $ echo '{"title": "Title", "message": "Hello World!!"}' | fluent-cat growl.test $ echo '{"title": "Sticky", "message": "It's sticky message!!", notify:"StickyNotify"}' | fluent-cat growl.test $ echo '{}' | fluent-cat growl.test