su(1): Add -g flag
AcceptedPublic
Actions

Authored by fernape on Aug 1 2025, 4:26 PM.

Details

Reviewers

0mp
bcr
carlavilla

Group Reviewers

manpages
Src Committers

Summary

As an alias to -c to avoid confusion with the flag provided by most shells.

This should avoid confusion when using two -c in one command.

While here improve the manual page a bit

Comes from: https://reviews.freebsd.org/D26941 done by @0mp

Test Plan

Apply patch.

Test commands from the EXAMPLES section.
mandoc -T lint clean.

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Skipped

Unit

Tests Skipped

Build Status

Buildable 65899
Build 62782: arc lint + arc unit

Event Timeline

fernape created this revision.Aug 1 2025, 4:26 PM

Herald added subscribers: ziaee, imp. · View Herald TranscriptAug 1 2025, 4:26 PM

fernape requested review of this revision.Aug 1 2025, 4:26 PM

Harbormaster completed remote builds in B65899: Diff 159582.Aug 1 2025, 4:26 PM

fernape edited the summary of this revision. (Show Details)Aug 1 2025, 4:31 PM

fernape edited the test plan for this revision. (Show Details)

fernape added reviewers: 0mp, bcr, manpages, Src Committers.

fernape added a subscriber: 0mp.

Ok for the doc side

This revision is now accepted and ready to land.Aug 1 2025, 10:20 PM

fernape mentioned this in D26941: su.1: Try to clarify confusing -c options.Apr 26 2026, 3:52 PM

Friendly ping! 🔔

This change seems like it would cause further confusion.
The Linux [coreutils'] version of su uses -g for overriding the primary group and -G to specify the supplementary group: https://www.man7.org/linux/man-pages/man1/su.1.html .
In an ideal world, I honestly think it would be best to rename -c to -C for symmetry with other utilities, but I'm sure that would cause loads of teeth gnashing and complaining from folks since -c has meant "class" since 1997 (renaming the option would break UX for a lot of scripts).
-C seems appropriate here, if nothing else... but I'm not sure this change is necessary. What issue are you ultimately trying to solve and what lead you to this conclusion?

In D51683#1359560, @ngie wrote:

This change seems like it would cause further confusion.
The Linux [coreutils'] version of su uses -g for overriding the primary group and -G to specify the supplementary group: https://www.man7.org/linux/man-pages/man1/su.1.html .
In an ideal world, I honestly think it would be best to rename -c to -C for symmetry with other utilities, but I'm sure that would cause loads of teeth gnashing and complaining from folks since -c has meant "class" since 1997 (renaming the option would break UX for a lot of scripts).
-C seems appropriate here, if nothing else... but I'm not sure this change is necessary. What issue are you ultimately trying to solve and what lead you to this conclusion?

I can't find it, but this was triggered by an email in our lists where someone complained about su not behaving correctly, and took a few mails to actually understand what was going on (basically that -c from su was being subtly being mixed up with -c from the shell in the same invocation). If memory serves, it was des@ the one who finally clarified the issue. The idea to provide an alias keeps compatibility and provides an alternative to disambiguate when necessary.