On 26/02/2026 05:02, Collin Funk wrote:
The change in behavior can be seen with the invocations below:
$ time ./src/groups-prev $(yes collin | head -n 10000 | tr '\n' ' ') >&-
groups-prev: write error: Bad file descriptor
real 0m35.295s
user 0m9.271s
sys 0m17.325s
$ time ./src/groups $(yes collin | head -n 10000 | tr '\n' ' ') >&-
groups: write error: Bad file descriptor
real 0m0.021s
user 0m0.006s
sys 0m0.018s
-- 8< --
* NEWS: Mention the improvement.
* src/groups.c (main): Call fflush for each listed user to check for
write errors.
---
NEWS | 3 +++
src/groups.c | 3 +++
2 files changed, 6 insertions(+)
diff --git a/NEWS b/NEWS
index cf1b1414e..13bb6031a 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,9 @@ GNU coreutils NEWS -*-
outline -*-
** Improvements
+ 'group' will now exit immediately upon receiving a write error, which is
+ significant when listing information for many users.
s/group/groups/
Also you might squash this in for tests:
diff --git a/tests/misc/io-errors.sh b/tests/misc/io-errors.sh
index 63649603e..e947df142 100755
--- a/tests/misc/io-errors.sh
+++ b/tests/misc/io-errors.sh
@@ -44,7 +44,9 @@ fmt foo
fold foo
fold -b foo
fold -c foo
+groups
head -n1 foo
+id
join foo foo
nl foo
numfmt --invalid=ignore < foo
Otherwise looks good.
cheers,
Padraig
