nvme: do not print status message on default

[igaw]

Unix tools should remain silent on success and produce output only when it is part of their functional result. Emitting status messages by default violates the long-established convention that stdout is reserved for machine-consumable data, while diagnostics and optional progress reporting belong on stderr or behind an explicit verbose flag.

A core strength of Unix tooling is composability: commands are routinely used in pipelines, shell scripts, automation frameworks, and other programs. Unsolicited status output contaminates stdout, forcing consumers to implement fragile filtering logic and making the tool harder to integrate reliably. The absence of default status messages is therefore not merely a stylistic preference but an interoperability requirement.

This follows the traditional Unix principle that "no news is good news": successful execution is indicated by the exit status, not by human-readable confirmation text. Users who need operational visibility can opt into it through verbose or progress-reporting options, while automation and existing workflows continue to receive clean, deterministic output.

Fixes: #2025

[note: there are plenty more places where nvme-cli still prints directly to stdout. this needs to be updated as well. but given the size of this tasks, let's go incrementatlly]

[Copilot]

Pull request overview

This PR reduces unsolicited “success”/status output from nvme commands by moving many messages behind a new “verbose-only message” helper, aligning default behavior with Unix composability expectations (clean stdout on success).

Changes:

• Replace a number of unconditional success printf()/fprintf() calls with nvme_show_verbose_result() / nvme_show_verbose_info().
• Add nvme_show_verbose_message() to centralize verbose-only messaging in the print layer.
• Suppress namespace-management success status output unless --verbose is set.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
nvme.c	Converts many success/status messages to verbose-only output and adjusts namespace-management status printing.
nvme-print.h	Adds convenience macros for verbose-only messaging.
nvme-print.c	Implements nvme_show_verbose_message() to gate status output behind verbosity and output format handling.

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[igaw]

$ ./nvme write /dev/nvme0n1 --start-block=1023 --block-count=0 --data-size=512 --data=nvmetests/TestNVMeCompareCmd/write_file.txt
$ ./nvme write /dev/nvme0n1 --start-block=1023 --block-count=0 --data-size=512 --data=nvmetests/TestNVMeCompareCmd/write_file.txt -v
write: Success
$ ./nvme write /dev/nvme0n1 --start-block=1023 --block-count=0 --data-size=512 --data=nvmetests/TestNVMeCompareCmd/write_file.txt -v -o json
{
  "result":"write: Success"
}

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

[igaw]

@copilot: what about this?

	if (!err && !nvme_args.verbose && nvme_is_output_format_normal())
		return;

[igaw]

I realize there is a bit more work to do here. Especially if we want to split progress/status infos as unix tool wants to have.

Also the whole flag parsing around nvme_args.output_format should be made more sane, that is we parse it once and store it globally in something like nvme_args.output_format_flags.