Fix a bug in the built-in echo in /bin/sh reported in private mail by
Oguz <oguzismailuysal@gmail.com>

If echo detects an I/O error, it does exit(1) (that's fine) but then
the next echo also does exit(1) even without any errors of its own,
and every following echo writing to stdout does the same thing.

eg:

echo foo >&- ; echo $?; echo $?; ( echo $( echo $?; echo $?) ; echo $? )
1
1
1 1
1

The first echo writes nothing (stdout is closed) but does exit(1).
The second echo writes "1" (correct, the exit status of the previous
echo) and should exit(0) - but doesn't. This pattern continues...

While here, conform to the POSIX requirement on echo (and many other
standard utilities, but definitely not all) that when the utility
does exit(>0) a message must be written to stderr (and vice versa
in many cases). Our echo (as shown above) did the exit(1) part
when it detected the I/O error, but no message is sent to stderr.
Fix that while we're here.

Similar changes are required for /bin/echo (coming soon), and
/usr/bin/printf (which is also the sh builtin printf) - except
currently that one kind of conforms, as it ignores errors writing
to stdout (as do large numbers of other utilities). For many
programs that's kind of acceptable, but where the sole purpose of
the program is to write to stdout, it really isn't. Also to be
fixed soon.

branches: 1.14.62;
output.c output.h: expose OUTPUT_ERR (flag for an exposed flags variable)
bltin.h: support ferror()
echo.c: use ferror() to fail on output write errors

Another piece of PR bin/39574.

use __RCSID()

branches: 1.12.10; 1.12.16;
remove obsolete register declarations

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Spell output with two ts.

Fixes from David Laight:
- ansification
- format of output of jobs command (etc)
- job identiers %+, %- etc
- $? and $(...)
- correct quoting of output of set, export -p and readonly -p
- differentiation between nornal and 'posix special' builtins
- correct behaviour (posix) for errors on builtins and special builtins
- builtin printf and kill
- set -o debug (if compiled with DEBUG)
- cd src obj (as ksh - too useful to do without)
- unset -e name, remove non-readonly variable from export list.
(so I could unset -e PS1 before running the test shell...)

Fix problems that gcc -Wall found (from Todd Miller, OpenBSD)

branches: 1.7.6;
convert to new RCS id conventions.

Add RCS ids.

sync with 4.4lite

Add RCS identifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

branches: 1.1.1;
Initial revision

output.c output.h: expose OUTPUT_ERR (flag for an exposed flags variable)
bltin.h: support ferror()
echo.c: use ferror() to fail on output write errors

Another piece of PR bin/39574.

use __RCSID()

branches: 1.12.10; 1.12.16;
remove obsolete register declarations

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Spell output with two ts.

Fixes from David Laight:
- ansification
- format of output of jobs command (etc)
- job identiers %+, %- etc
- $? and $(...)
- correct quoting of output of set, export -p and readonly -p
- differentiation between nornal and 'posix special' builtins
- correct behaviour (posix) for errors on builtins and special builtins
- builtin printf and kill
- set -o debug (if compiled with DEBUG)
- cd src obj (as ksh - too useful to do without)
- unset -e name, remove non-readonly variable from export list.
(so I could unset -e PS1 before running the test shell...)

Fix problems that gcc -Wall found (from Todd Miller, OpenBSD)

branches: 1.7.6;
convert to new RCS id conventions.

Add RCS ids.

sync with 4.4lite

Add RCS identifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

branches: 1.1.1;
Initial revision

44lite code

initial import of 386bsd-0.1 sources

Update /bin/sh from trunk per request of Christos Zoulas. Fixes
many bugs.

sync with HEAD

Pull up following revision(s) (requested by dholland in ticket #1232):
bin/echo/echo.c: revision 1.18
bin/sh/bltin/bltin.h: revision 1.13
bin/sh/bltin/echo.c: revision 1.14
bin/sh/output.c: revision 1.30
bin/sh/output.h: revision 1.19
Check ferror(stdout) and exit(1) if there's been a problem.
Fixes PR bin/39574 from Ed Ravin, but with a simpler patch.
output.c output.h: expose OUTPUT_ERR (flag for an exposed flags variable)
bltin.h: support ferror()
echo.c: use ferror() to fail on output write errors
Another piece of PR bin/39574.