almahdi <budikus...@gmail.com> writes:
> How do we intercept and redirect file saving or output to stdout directly in
> bash, just like e.g
>
> xkbcomp $DISPLAY
>
> will output and generated a file, but what needed is to put it directly to
> stream of stdout which will be piped once.
...
> $ xkbcomp $DISPLAY /dev/stdout
> Error: Cannot open "/dev/stdout" to write keyboard description
> Exiting
Normally, that should work.
But I get the same error message as you do. I did a trace on xkbcom and
I see at the end:
open("/dev/stdout", O_WRONLY|O_CREAT|O_EXCL, 0666) = -1 EEXIST (File exists)
write(2, "Error: ", 18Error: ) = 18
write(2, "Cannot open \"/dev/stdout\" to wri"..., 56Cannot open "/dev/stdout"
to write keyboard description
) = 56
The open() is done with the O_EXCL flag. Reading the manual page
open(2), I see that O_EXCL requires that the open() call creates the
file.
It's not clear why xkbcomp has this behavior, but it seems likely that
this is done for a specific reason. So you will have to ask whoever
maintains it.
I don't see any option that overrides this behavior.
However, as Robert said, many programs handle an argument "-" specially
as a reference to stdin or stdout. And it turns out that (my version
of) xkbcomp does so:
$ xkbcomp $DISPLAY -
xkb_keymap {
xkb_keycodes "evdev+aliases(qwerty)" {
minimum = 8;
maximum = 255;
<ESC> = 9;
<AE01> = 10;
...
Dale
