Adding upstream version 1.44.3.upstream/1.44.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 47 insertions, 0 deletions

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+<!--
+title: "Simple patterns"
+description: "Netdata supports simple patterns, which are less cryptic versions of regular expressions. Use familiar notation for powerful results."
+custom_edit_url: https://github.com/netdata/netdata/edit/master/libnetdata/simple_pattern/README.md
+sidebar_label: "Simple patterns"
+learn_status: "Published"
+learn_topic_type: "Tasks"
+learn_rel_path: "Developers/libnetdata"
+-->
+
+# Simple patterns
+
+Unix prefers regular expressions. But they are just too hard, too cryptic
+to use, write and understand.
+
+So, Netdata supports **simple patterns**.
+
+Simple patterns are a space separated list of words, that can have `*`
+as a wildcard. Each word may use any number of `*`. Simple patterns
+allow **negative** matches by prefixing a word with `!`.
+
+So, `pattern = !*bad* *` will match anything, except all those that
+contain the word `bad`. 
+
+Simple patterns are quite powerful: `pattern = *foobar* !foo* !*bar *`
+matches everything containing `foobar`, except strings that start
+with `foo` or end with `bar`.
+
+You can use the Netdata command line to check simple patterns,
+like this:
+
+```sh
+# netdata -W simple-pattern '*foobar* !foo* !*bar *' 'hello world'
+RESULT: MATCHED - pattern '*foobar* !foo* !*bar *' matches 'hello world'
+
+# netdata -W simple-pattern '*foobar* !foo* !*bar *' 'hello world bar'
+RESULT: NOT MATCHED - pattern '*foobar* !foo* !*bar *' does not match 'hello world bar'
+
+# netdata -W simple-pattern '*foobar* !foo* !*bar *' 'hello world foobar'
+RESULT: MATCHED - pattern '*foobar* !foo* !*bar *' matches 'hello world foobar'
+```
+
+Netdata stops processing to the first positive or negative match
+(left to right). If it is not matched by either positive or negative
+patterns, it is denied at the end.
+
+