#!/usr/bin/env osh
:
: osh - " Force sh(1), csh(1), and other shells to exit w/ error! " <'' ;;;
:
: "  @(#)$Id: fd0to2.osh 534 2008-10-31 21:21:06Z jneitzel $  "
:
: "  The author of this file, J.A. Neitzel <jan (at) v6shell (dot) org>,  "
: "  hereby grants it to the public domain.                               "
:

:
: "  NOTE: The new fd2 `-e' command-line option in osh-20081026 obviates  "
: "	   the need for this command file.                                "
:

:
: "  Read data from file descriptor 0 and write it to file descriptor 2.  "
: "  However, in the case where writing to file descriptor 2 would fail,  "
: "  attempt to write the data to `/dev/tty' as the default case.  Data   "
: "  may come from a regular file, a FIFO, or a pipe.  It may not come    "
: "  from a terminal device; a diagnostic is printed in such a case.      "
:
: "  It is assumed that the format of the ``data'' is ``text'' which can  "
: "  be safely written to a terminal device, but this is not enforced.    "
:
: "  If the length of the data is greater than zero bytes, exit with a    "
: "  non-zero status; otherwise, exit with a zero status.                 "
:
: "  usage: fd0to2  "
:

:
: " Check for expected script name. "
:
: >>$0'' <''
killer $0'' fd0to2

:
: " Perform all necessary actions for setup:                       "
:
: "	1) Create a temporary directory;                           "
: "	2) Test if data would come from a tty, and exit if true;   "
: "	3) Read data (if any), and write it to a temporary file;   "
: "	4) Test size of data, and exit or continue as appropriate. "
:
if ! { mkdir -m 0700 /tmp/fd0to2-$$ } if { exit } false
if -t 0 <-
if $s != 0 goto Not_a_tty
	echo 'fd0to2: '$t': Invalid data source' >/dev/tty
	rmdir /tmp/fd0to2-$$ ; false ; exit
: Not_a_tty
	cat <- >/tmp/fd0to2-$$/data
	if ! -s /tmp/fd0to2-$$/data if { rm -rf /tmp/fd0to2-$$ } exit

:
: " Write the data to the appropriate destination. "
:
if -w /dev/stderr goto STDERR
if -w /dev/fd/2   goto FD2
: default
	cat </tmp/fd0to2-$$/data >/dev/tty ; goto Done

: STDERR
	cat </tmp/fd0to2-$$/data >/dev/stderr ; goto Done

: FD2
	cat </tmp/fd0to2-$$/data >/dev/fd/2

: Done
	rm -rf /tmp/fd0to2-$$ ; false