diff subshell redirection fails

[Harald Becker]

Hi Jose,

I'm not sure if I fully understand your questions, but here are some
suggestions. May be they help to clarify things.

>Trying to use redirection subshell with busybox diff, ...

1) Redirection subshell is a bash-ism and as far as I know not
implemented in Busybox.

2) The diff command works only on regular files and directories and may
fail or neglect operation on special files.

>$ ./busybox diff <(ls /var) <(ls -1 /var)

That way your current shell (usually bash) does the redirection, not the
Busybox you build. Only the command invoked after doing redirection is
the diff applet of Busybox. As input is not from regular files it may
neglect operation. IMO it shall give a diagnostic message in this case,
but may be it is skipped to allow for easy recursive operation (just
skipping entries which are not regular files).

>$ ./busybox comm <(ls /var) <(ls -1 /var)

Same as above, your current shell does redirection not the Busybox you
build. The command invoked is the Busybox comm applet. This applet
allows input from special files so it works as expected.

--
Harald