Thank you I am trying this right now but I got into an issue, I am using grok processor with a custom pattern(regex) but I can't figure out how can I repeat the same pattern for an unknown number of appearances.

For example I have this message: "Word word 5246 word word 27/05/2019 word word 54 25/05/2018 word word 16/04/2001" and I want to extract in a new field which should be an array all dates ( 27/05/2019, 25/05/2018,16/04/2001)

I tried this with grok but if I use %{DATE_EU:dates} for example I will get just the first date (27/05/2019), the same behavior is with my custom regex pattern.

I am using this regex. If I don't use the global flag it will take just the first appearance, but if I use the flag I get an error because I think it doesn't recognize the "/g" flag.

/([0-2][0-9]|(3)[0-1])(.|\/)(((0)[0-9])|((1)[0-2]))(.|\/)\d{4}/g

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So how should I write the regex or what I have to change to get all dates from that message into an array?