cmd/modgraphviz: make it a more idiomatic Go command

- Doc comment for command begins with "Name", not "The name command".
- Doc comment usage line is in a code block, not plain text.
- Drop GO111MODULE=on from usage text
  (if people have a module, they have modules on).
- Doc comment text explains usage precisely, beyond usage line.
- Add references to what Graphviz is and also digraph tool.
- Turn off the date/time/file log annotations.
- Print command name as a log prefix.
- Don't print usage message using log.
- Check command-line argument count.
- Change Run(Reader, Writer) to convert(Reader) ([]byte, error)
  to avoid unnecessary error checks on bytes.Buffer.Write
  (which can't fail).
- io.Reader should be named r, not in.
- Use idiomatic bufio.Scanner loop, like in its example.

Change-Id: I74f1a9f58e2dada87eab483183a92eff9ff31cbf
Run-TryBot: Russ Cox <>
TryBot-Result: Gobot Gobot <>
Reviewed-by: Dmitri Shuralyov <>
2 files changed
tree: 83d7c41f6bc46b12ab512007abdc5e1269e57b82
  1. .gitattributes
  2. .gitignore
  9. apidiff/
  10. cmd/
  11. codereview.cfg
  12. ebnf/
  13. ebnflint/
  14. errors/
  15. fsnotify/
  16. go.mod
  17. go.sum
  18. inotify/
  19. io/
  20. mmap/
  21. old/
  22. rand/
  23. shiny/
  24. shootout/
  25. sumdb/
  26. utf8string/
  27. winfsnotify/


This subrepository holds experimental and deprecated (in the old directory) packages.

The idea for this subrepository originated as the pkg/exp directory of the main repository, but its presence there made it unavailable to users of the binary downloads of the Go installation. The subrepository has therefore been created to make it possible to go get these packages.

Warning: Packages here are experimental and unreliable. Some may one day be promoted to the main repository or other subrepository, or they may be modified arbitrarily or even disappear altogether.

In short, code in this subrepository is not subject to the Go 1 compatibility promise. (No subrepo is, but the promise is even more likely to be violated by go.exp than the others.)

Caveat emptor.