bash 2.05b 'echo' incompatibility with POSIX-2004 and SUSv2

[Paul Eggert]

Configuration Information [Automatically generated, do not change]:
Machine: sparc
OS: solaris2.9
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='sparc' 
-DCONF_OSTYPE='solaris2.9' -DCONF_MACHTYPE='sparc-sun-solaris2.9' 
-DCONF_VENDOR='sun' -DSHELL  -DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib  -g 
-O2 -Wall -W -Wno-sign-compare -Wpointer-arith -Wstrict-prototypes 
-Wmissing-prototypes -Wmissing-noreturn -Wmissing-format-attribute
uname output: SunOS pete.twinsun.com 5.9 Generic_112233-12 sun4u sparc 
SUNW,UltraAX-i2
Machine Type: sparc-sun-solaris2.9

Bash Version: 2.05b
Patch Level: 0
Release Status: release

Description:
        POSIX says that the command "echo -e" must output the string "-e",
        but Bash's builtin "echo" command outputs nothing, even in
        POSIX-conforming mode.  Similarly, SUSv2 says that "echo -n"
        must output "-n", but Bash's "echo" outputs nothing, even
        when the xpg_echo option is on and POSIX-conforming mode is in effect.

        References:

        POSIX-2004 spec for 'echo':
        http://www.opengroup.org/onlinepubs/009695399/utilities/echo.html

        SUSv2 spec for 'echo':
        http://www.opengroup.org/onlinepubs/007908799/xcu/echo.html

Repeat-By:

        $ bash --posix
        1-red $ echo -e foo
        foo
        2-red $ shopt -s xpg_echo
        3-red $ echo -n foo
        foo4-red $ 

Fix:

The following patch affects Bash's behavior only when in
POSIX-conforming mode.  I'll send a similar patch to bug-coreutils so
that its "echo" is also fixed.

===================================================================
RCS file: doc/bashref.texi,v
retrieving revision 2.5.2.1
retrieving revision 2.5.2.2
diff -pu -r2.5.2.1 -r2.5.2.2
--- doc/bashref.texi    2003/09/26 20:24:50     2.5.2.1
+++ doc/bashref.texi    2004/05/13 01:07:41     2.5.2.2
@@ -3518,7 +3518,8 @@ This option is enabled by default.
 
 @item xpg_echo
 If set, the @code{echo} builtin expands backslash-escape sequences
-by default.
+by default, and outputs arguments like @option{-n} instead of treating
+them as options.
 
 @end table
 
@@ -5607,6 +5608,13 @@ The @code{export} and @code{readonly} bu
 output in the format required by @sc{posix} 1003.2.
 
 @item
+The @code{echo} command outputs option-like arguments instead of
+treating them as options if the @code{xpg_echo} shell option is on or
+if @code{echo}'s first argument is not @samp{-n}.  For example,
+@code{echo -ne hello} outputs @samp{-ne hello} instead of plain
+@samp{hello}.
+
+@item
 The @code{trap} builtin displays signal names without the leading
 @code{SIG}.
 
===================================================================
RCS file: builtins/echo.def,v
retrieving revision 2.5.2.0
retrieving revision 2.5.2.1
diff -pu -r2.5.2.0 -r2.5.2.1
--- builtins/echo.def   2002/03/19 15:45:28     2.5.2.0
+++ builtins/echo.def   2004/05/13 01:07:41     2.5.2.1
@@ -31,6 +31,8 @@ $PRODUCES echo.c
 #include <stdio.h>
 #include "../shell.h"
 
+extern int posixly_correct;
+
 $BUILTIN echo
 $FUNCTION echo_builtin
 $DEPENDS_ON V9_ECHO
@@ -91,6 +93,11 @@ echo_builtin (list)
   do_v9 = xpg_echo;
   display_return = 1;
 
+  if (posixly_correct
+      && (xpg_echo
+         || !(list && (temp = list->word->word) && strcmp (temp, "-n") == 0)))
+    goto just_echo;
+
   for (; list && (temp = list->word->word) && *temp == '-'; list = list->next)
     {
       /* If it appears that we are handling options, then make sure that