文档不相同：

gofmt -h
usage: gofmt [flags] [path ...]                                  -cpuprofile string                                                   write cpu profile to this file                           -d    display diffs instead of rewriting files                 -e    report all errors (not just the first 10 on different lines)                                                            -l    list files whose formatting differs from gofmt's         -r string                                                            rewrite rule (e.g., 'a[b:len(a)] -> a[b:]')              -s    simplify code                                            -w    write result to (source) file instead of stdout

和 https://golang.org/cmd/gofmt/