It's not clear to me how WriteString can fail here?

// WriteString appends the contents of s to b's buffer.
// It returns the length of s and a nil error.
func (b *Builder) WriteString(s string) (int, error) {
	b.copyCheck()
	b.buf = append(b.buf, s...)
	return len(s), nil
}

I would rather have something like _, _ = s.WriteString("-")

This sounds reasonable. This could also be a good solution for the flag parsing issues @rminnich stated.

rather than the no lint: thing, you ought to be able to say
func reply(_ io.Writer, r byte) {...}

If golangci-lint does not understand this, then it does not understand go.

Again, the common way to indicate an unused parameter is
func f(_ int, something int)
does golangci-lint not understand this?
I really don't like these no lint: things everywhere. It means, when code changes, people also need to understand to change the nolint, and they will forget. And then we'll have a bogus no lint directive. It's why these extraterritorial things are such a problem.
Does golangci-lint understand _ parameters? If not, it should.

Just confirmed: _ the param and golangci-lint will not complain.
remove this nolint: there is a Go-standard way to do this.

and if we have all these unused parameters, why don't we just fix the code?

so we have code we don't understand that we're patching up with no lint directives? Kinda nasty?

This looks good. This one change is a case for making this into more than one PR. It's SO BIT, it's exhausting to read.

this is just so ugly, but I guess we have no choice, but yuck.

This is the wrong fix.
What should be done is to use errors.Join
so this command and the nolint: actually make things worse.
This is why I am so concerned about this PR. It is guiding people to do the wrong thing.

OK, I just now tested this change:

-func getArg(b *bufio.Reader, what string) string {
+func getArg(b *bufio.Reader, _ string) string {

rminnich@sidecore:~/go/src/github.com/u-root/u-root$ golangci-lint run cmds/exp/rush/parse.go
rminnich@sidecore:~/go/src/github.com/u-root/u-root$ 

golangci-lint is fine with _ parameters.

So, the fix in the PR is the wrong fix. Adding the nolint: makes things worse.

Either remove what, which is the better solution; or make it _ string.

I would bet that just about every nolint: in this PR could be done a better way.

If you do a TODO, it will never get done. Let's fix this right.

Just confirmed: _ the param and golangci-lint will not complain.
remove this nolint: there is a Go-standard way to do this.