Update README.md

README.md

@@ -1,7 +1,7 @@
 # lograte
 
 A small tool ([used to be](https://github.com/vearutop/lograte/blob/v0.1.0/main.go) ~25 lines of code) to calculate the 
-rate of lines in STDOUT and group by them by count with alphanumeric filter.
+rate of lines in STDOUT and group them by count with alphanumeric filter.
 
 ## Installation
 
@@ -44,7 +44,11 @@ ssh -C log-collector.acme.com 'tail -f /var/log/app-error.log | grep "my feature
 6862 lines since Mar  3 23:46:32, 605.47 per second
 ```
 
-Or show top filtered messages by count or total size.
+Or show top filtered messages by count or total size. 
+
+> **_NOTE:_** Filtered messages have all case insensitive sequences of `[a-z]-_%` with at least one digit or all digits replaced with `X`. 
+> This is usually enough to remove dynamic data from message and decrease cardinality.
+> Filtered messages are collected in a limited number of buckets, once the limit is met all other messages are collected into the `Other` bucket.
 
 ```
 tail -f /var/log/quick.log | lograte -top 5 -t 1s -by-size
@@ -54,8 +58,31 @@ tail -f /var/log/quick.log | lograte -top 5 -t 1s -by-size
 foo-bar-18 i2 2022/09/03 08:22:17.206522 <recent log entry>
 271382 lines since Sep  3 08:22:14, 90447.4 per second, 68.3 MB/s, 791 B/avg
 ------ Top 5 -------------------------
-29810 lines, 9935.2 lps (11.0%), 14.7 MB/s (21.5%), 1546 B/avg: X X X/X/X X:X:X.X filtered entry 
-26559 lines, 8851.7 lps (9.8%), 9.1 MB/s (13.4%), 1083 B/avg: X X X/X/X X:X:X.X another filtered entry
+29810 lines, 9935.2 lps (11.0%), 14.7 MB/s (21.5%), 1546 B/avg: X X X/X/X X:X:X.X filtered entry X.X
+26559 lines, 8851.7 lps (9.8%), 9.1 MB/s (13.4%), 1083 B/avg: X X X/X/X X:X:X.X another filtered X entry
 ...
 ---------------------------------------
 ```
+
+### Flags
+
+```
+lograte -help
+```
+```
+Usage of lograte:
+  -buckets int
+    	max number of buckets to track filtered messages (default 500)
+  -by-size
+    	order messages by size instead of count
+  -len int
+    	limit message length (default 120)
+  -line-buf int
+    	line token buffer size (default 10000000)
+  -t duration
+    	reporting interval (default 1s)
+  -top int
+    	show top filtered messages ordered by rate
+  -version
+    	print version and exit
+```