Update readme.md for grep and jq

I propose adding a JQ command and updating the current grep so it matches the output and doesn't  just match the whole string.

Author: davidsandilands

README.md

@@ -133,7 +133,7 @@ Defaults to `undef`.
 ## Usage
 
 
-### Grepping Metrics
+### Searching Metrics
 
 Metrics are formatted as a JSON hash on one line.
 In order to convert the metric files into a multi-line format, they can be processed with `python -m json.tool` as per below.
@@ -143,40 +143,68 @@ cd /opt/puppetlabs/puppet-metrics-collector
 for i in <service_name>/primary.example.com/*.json; do echo "$(python -m json.tool < $i)" > $i; done
 ```
 
-You can search for useful information by performing a `grep`, run from inside the directory containing the metrics.
+You can search for useful information by performing a `grep`, run from inside the directory containing the metrics
 
 ```bash
 cd /opt/puppetlabs/puppet-metrics-collector
-grep <metric_name> <service_name>/primary.example.com/*.json
+grep -oP '"<metric_name>,*?,' <service_name>/primary.example.com/*.json
+```
+
+or JQ if available
+```bash
+cd /opt/puppetlabs/puppet-metrics-collector
+jq '.. |."<metric_name>"? | select(. != null)| input_filename , .' -- <service_name>/primary.example.com/*.json
 ```
 
 Since the metrics are archived once per day, you can only search metrics for the current day.
 To search older metrics, decompress the archived files into a subdirectory of `/tmp` and run your search from inside that directory.
 
-#### Grepping Puppetserver Metrics
+#### Searching Puppetserver Metrics
 
 Example:
 
 ```bash
-grep average-free-jrubies puppetserver/primary.example.com/*.json
+grep -oP '"average-free-jrubies.*?,' puppetserver/primary.example.com/*.json
+
+puppetserver/primary.example.com/20190404T170501Z.json:"average-free-jrubies":0.9950009285369501,
+puppetserver/primary.example.com/20190404T171001Z.json:"average-free-jrubies":0.9999444653324225,
+puppetserver/primary.example.com/20190404T171502Z.json:"average-free-jrubies":0.9999993830655706,
+```
 
-puppetserver/primary.example.com/20190404T170501Z.json: "average-free-jrubies": 0.9950009285369501,
-puppetserver/primary.example.com/20190404T171001Z.json: "average-free-jrubies": 0.9999444653324225,
-puppetserver/primary.example.com/20190404T171502Z.json: "average-free-jrubies": 0.9999993830655706,
+```bash
+jq '.. |."average-free-jrubies"? | select(. != null)| input_filename , .' -- puppetserver/primary.example.com/*.json
+
+"puppetserver/primary.example.com/20190404T170501Z.json"
+0.9950009285369501
+"puppetserver/primary.example.com/20190404T171001Z.json"
+0.9999444653324225,
+"puppetserver/primary.example.com/20190404T171502Z.json"
+0.9999993830655706,
 ```
 
-#### Grepping PuppetDB Metrics
+#### Searching PuppetDB Metrics
 
 Example:
 
 ```bash
-grep queue_depth puppetdb/primary.example.com/*.json
+grep -oP '"queue_depth.*?,' puppetdb/primary.example.com/*.json
 
 puppetdb/primary.example.com/20190404T170501Z.json: "queue_depth": 0,
 puppetdb/primary.example.com/20190404T171001Z.json: "queue_depth": 0,
 puppetdb/primary.example.com/20190404T171502Z.json: "queue_depth": 0,
 ```
 
+```bash
+jq '.. |."queue_depth "? | select(. != null)| input_filename , .' -- puppetdb/primary.example.com/*.json
+
+"puppetdb/primary.example.com/20190404T170501Z.json"
+0
+"puppetdb/primary.example.com/20190404T171001Z.json"
+0
+"puppetdb/primary.example.com/20190404T171502Z.json" 
+0
+```
+
 ### Sharing Metrics Data
 
 When working with Support, you may be asked for an archive of collected metrics data.