wrongdoc: add usage info when erroring

I forgot how to use it myself

1 files changed, 4 insertions, 2 deletions

diff --git a/bin/wrongdoc b/bin/wrongdoc
index d33feda..5e6bd36 100644
--- a/bin/wrongdoc
+++ b/bin/wrongdoc
@@ -1,5 +1,6 @@
 #!/usr/bin/env ruby
-usage = "Usage: #{File.basename($0)} [prepare]"
+tasks = %w(prepare release_notes release_changes all)
+usage = "Usage: #{File.basename($0)} [#{tasks.join('|')}]"
 $stderr.sync = $stdout.sync = true
 require 'wrongdoc'
 opts = Wrongdoc.config
@@ -16,5 +17,6 @@ when "all"
   Wrongdoc::Merge.new(opts).run
   Wrongdoc::Final.new(opts, ARGV[1]).run
 else
-  abort "#{$0.inspect} #{ARGV.inspect} not understood"
+  warn "#{$0.inspect} #{ARGV.inspect} not understood"
+  abort usage
 end