Add a few more instructions to logcli --help. (#2948)

Signed-off-by: Tom Wilkie <[email protected]>

cmd/logcli/main.go

@@ -47,10 +47,14 @@ and its results, such as the API URL, set of common labels, and set
 of excluded labels. This extra information can be suppressed with the
 --quiet flag.
 
+By default we look over the last hour of data; use --since to modify
+or provide specific start and end times with --start and --end.
+The output is limited to 30 entries by default; use --limit to increase.
+
 While "query" does support metrics queries, its output contains multiple
 data points between the start and end query time. This output is used to
-build graphs, like what is seen in the Grafana Explore graph view. If
-you are querying metrics and just want the most recent data point
+build graphs, similar to what is seen in the Grafana Explore graph view.
+If you are querying metrics and just want the most recent data point
 (like what is seen in the Grafana Explore table view), then you should use
 the "instant-query" command instead.`)
 	rangeQuery = newQuery(false, queryCmd)
@@ -78,13 +82,13 @@ https://github.com/grafana/loki/blob/master/docs/logql.md`)
 
 	seriesCmd = app.Command("series", `Run series query.
 
-The "series" command will take the provided label matcher 
+The "series" command will take the provided label matcher
 and return all the log streams found in the time window.
 
 It is possible to send an empty label matcher '{}' to return all streams.
 
 Use the --analyze-labels flag to get a summary of the labels found in all streams.
-This is helpful to find high cardinality labels. 
+This is helpful to find high cardinality labels.
 `)
 	seriesQuery = newSeriesQuery(seriesCmd)
 )