On Sun, Mar 12, 2023, at 1:35 PM, Robert Elz via austin-group-l at The Open
Group wrote:
> With the GNU version, what would be more interesting to know, is what
> it does when run as
> true --nonsense
> true ----------
> true '--:) (-;'
> (and similar). What's the exit status, is there any output, and if
> so, to stdout or stderr?
% /opt/local/libexec/gnubin/true --nonsense; echo "$?"
0
% /opt/local/libexec/gnubin/true ----------; echo "$?"
0
% /opt/local/libexec/gnubin/true '--:) (-;'; echo "$?"
0
> I'm also assuming that the --version and --help (to be meaningful "accepted"
> rather than just ignored - everyone's true allows and ignores those, and
> any other args given) actually produce some output. stdout or stderr?
They print messages to stdout.
> What happens (exit status etc) if there's a write error while writing that
> output?
% /opt/local/libexec/gnubin/true --version >&-; echo "$?"
true: write error: Bad file descriptor
1
Interestingly, the documentation anticipates this concern:
https://www.gnu.org/software/coreutils/manual/html_node/true-invocation.html
--
vq
