docs: document telegraf commands and flags (#9635)

docs/COMMANDS_AND_FLAGS.md

@@ -0,0 +1,67 @@
+# Telegraf Commands & Flags
+
+### Usage
+
+```
+telegraf [commands]
+telegraf [flags]
+```
+
+### Commands
+
+|command|description|
+|--------|-----------------------------------------------|
+|`config` |print out full sample configuration to stdout|
+|`version`|print the version to stdout|
+
+### Flags
+
+|flag|description|
+|-------------------|------------|
+|`--aggregator-filter <filter>`   |filter the aggregators to enable, separator is `:`|
+|`--config <file>`                |configuration file to load|
+|`--config-directory <directory>` |directory containing additional *.conf files|
+|`--watch-config`                 |Telegraf will restart on local config changes. <br> Monitor changes using either fs notifications or polling.  Valid values: `inotify` or `poll`.<br> Monitoring is off by default.|
+|`--plugin-directory`             |directory containing *.so files, this directory will be searched recursively. Any Plugin found will be loaded and namespaced.|
+|`--debug`                        |turn on debug logging|
+|`--input-filter <filter>`        |filter the inputs to enable, separator is `:`|
+|`--input-list`                   |print available input plugins.|
+|`--output-filter <filter>`       |filter the outputs to enable, separator is `:`|
+|`--output-list`                  |print available output plugins.|
+|`--pidfile <file>`               |file to write our pid to|
+|`--pprof-addr <address>`         |pprof address to listen on, don't activate pprof if empty|
+|`--processor-filter <filter>`    |filter the processors to enable, separator is `:`|
+|`--quiet`                        |run in quiet mode|
+|`--section-filter`               |filter config sections to output, separator is `:` <br> Valid values are `agent`, `global_tags`, `outputs`, `processors`, `aggregators` and `inputs`|
+|`--sample-config`                |print out full sample configuration|
+|`--once`                         |enable once mode: gather metrics once, write them, and exit|
+|`--test`                         |enable test mode: gather metrics once and print them|
+|`--test-wait`                    |wait up to this many seconds for service inputs to complete in test or once mode|
+|`--usage <plugin>`               |print usage for a plugin, ie, `telegraf --usage mysql`|
+|`--version`                      |display the version and exit|
+
+### Examples
+
+**Generate a telegraf config file:**
+
+`telegraf config > telegraf.conf`
+
+**Generate config with only cpu input & influxdb output plugins defined:**
+
+`telegraf --input-filter cpu --output-filter influxdb config`
+
+**Run a single telegraf collection, outputting metrics to stdout:**
+
+`telegraf --config telegraf.conf --test`
+
+**Run telegraf with all plugins defined in config file:**
+  
+`telegraf --config telegraf.conf`
+
+**Run telegraf, enabling the cpu & memory input, and influxdb output plugins:**
+
+`telegraf --config telegraf.conf --input-filter cpu:mem --output-filter influxdb`
+
+**Run telegraf with pprof:**
+
+`telegraf --config telegraf.conf --pprof-addr localhost:6060`

docs/CONFIGURATION.md

@@ -19,6 +19,8 @@ To generate a file with specific inputs and outputs, you can use the
 telegraf --input-filter cpu:mem:net:swap --output-filter influxdb:kafka config
 ```
 
+[View the full list][flags] of Telegraf commands and flags or by running `telegraf --help`.
+
 ### Configuration Loading
 
 The location of the configuration file can be set via the `--config` command
@@ -671,3 +673,4 @@ Reference the detailed [TLS][] documentation.
 [telegraf.conf]: /etc/telegraf.conf
 [TLS]: /docs/TLS.md
 [glob pattern]: https://github.com/gobwas/glob#syntax
+[flags]: /docs/COMMANDS_AND_FLAGS.md