From 84cae5a52d05a28a369276b5336c1b19e65064a8 Mon Sep 17 00:00:00 2001
From: Nathan John Youngman <nj@nathany.com>
Date: Tue, 24 Sep 2013 17:27:26 +1000
Subject: [PATCH] go.tools/cover: clean up usage information

R=golang-dev, r, minux.ma
CC=golang-dev
https://golang.org/cl/13532052
---
 cmd/cover/cover.go | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/cmd/cover/cover.go b/cmd/cover/cover.go
index 9fec01a1..3862cf71 100644
--- a/cmd/cover/cover.go
+++ b/cmd/cover/cover.go
@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // Cover is a program for analyzing the coverage profiles generated by
-// 'go test -coverprofile'.
+// 'go test -coverprofile=cover.out'.
 //
 // Cover is also used by 'go test -cover' to rewrite the source code with
 // annotations to track which parts of each function are executed.
@@ -12,6 +12,10 @@
 // than binary-rewriting coverage tools, but also a little less capable.
 // For instance, it does not probe inside && and || expressions, and can
 // be mildly confused by single statements with multiple function literals.
+//
+// For usage information, please see:
+//  go help testflag
+//  go tool cover -help
 package main
 
 import (
@@ -30,23 +34,28 @@ import (
 
 const usageMessage = "" +
 	`Usage of 'go tool cover':
-Given a coverage profile produced by 'go test -coverprofile=c.out', open
-a web browser displaying annotated source code:
-	go tool cover -html=c.out
-The same, but write the generated HTML to a file instead of starting a browser:
-	go tool cover -html=c.out -o coverage.html
-Write to standard output coverage percentages for each function:
-	go tool cover -func=c.out
-Generate modified source code with coverage annotations (what go test -cover does):
-	go tool cover  -mode=set -var=CoverageVariableName program.go
+Given a coverage profile produced by 'go test':
+	go test -coverprofile=c.out
 
-Only one of -html, -func, or -mode may be set.
+Open a web browser displaying annotated source code:
+	go tool cover -html=c.out
+
+Write out an HTML file instead of launching a web browser:
+	go tool cover -html=c.out -o coverage.html
+
+Display coverage percentages to stdout for each function:
+	go tool cover -func=c.out
+
+Finally, to generate modified source code with coverage annotations
+(what go test -cover does):
+	go tool cover -mode=set -var=CoverageVariableName program.go
 `
 
 func usage() {
 	fmt.Fprintln(os.Stderr, usageMessage)
 	fmt.Fprintln(os.Stderr, "Flags:")
 	flag.PrintDefaults()
+	fmt.Fprintln(os.Stderr, "\n  Only one of -html, -func, or -mode may be set.")
 	os.Exit(2)
 }