On Sun, Nov 03, 2024 at 11:28:24 +0100, Christoph Zimmermann wrote:
> Thanks for all the quick reactions on that issue (including microsuxx's
> suggestion which unfortunately does require a CB change).
>
> If this is intended behaviour, it should be clearly documented on the
> corresponding man page (which doesn't seem to be case ATM).
Hmm... you may have a point there. The bash man page documents -x as:
-x After expanding each simple command, for command, case
command, select command, or arithmetic for command, dis‐
play the expanded value of PS4, followed by the command
and its expanded arguments or associated word list.
whereas POSIX documents it as:
-x The shell shall write to standard error a trace for each command
after it expands the command and before it executes it. It is un‐
specified whether the command that turns tracing off is traced.
There's some *implication* that stderr might be the default in the bash
documentation of BASH_XTRACEFD:
BASH_XTRACEFD
If set to an integer corresponding to a valid file descriptor,
bash will write the trace output generated when set -x is en‐
abled to that file descriptor. The file descriptor is closed
when BASH_XTRACEFD is unset or assigned a new value. Unsetting
BASH_XTRACEFD or assigning it the empty string causes the trace
output to be sent to the standard error. Note that setting
BASH_XTRACEFD to 2 (the standard error file descriptor) and then
unsetting it will result in the standard error being closed.
but I agree that it could be made much clearer that stderr is the default
if BASH_XTRACEFD is never touched. Perhaps the -x paragraph should say
something like:
-x After expanding each simple command, for command, case
command, select command, or arithmetic for command, dis‐
play the expanded value of PS4, followed by the command
and its expanded arguments or associated word list,
to the file descriptor contained in BASH_XTRACEFD,
or standard error if BASH_XTRACEFD is empty or unset.
