doc: printf: detail exactly which escapes are supported

* doc/coreutils.texi (echo invocation): Parameterize the escape list.
(printf invocation): Remove the C escape reference as it mentions
\' which we don't support, and doesn't mention \e which we do support
(and GCC also does).  Instead directly present the escape list
as done for the echo command, adjusted accordingly.

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index e90fb3e14c2713bbdfb3efd803d4377eb898b20a..862c938e199736aa30a50fa0b9401e18e3499614 100644 (file)
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -12873,39 +12873,54 @@ Do not output the trailing newline.
 Enable interpretation of the following backslash-escaped characters in
 each @var{string}:
 
+@macro escapeSequences
 @table @samp
-@item \a
+@item \\\\
+backslash
+@ifset PRINTF_COMMAND
+@item \\"
+double quote
+@end ifset
+@item \\a
 alert (bell)
-@item \b
+@item \\b
 backspace
-@item \c
+@item \\c
 produce no further output
-@item \e
+@item \\e
 escape
-@item \f
+@item \\f
 form feed
-@item \n
+@item \\n
 newline
-@item \r
+@item \\r
 carriage return
-@item \t
+@item \\t
 horizontal tab
-@item \v
+@item \\v
 vertical tab
-@item \\
-backslash
-@item \0@var{nnn}
+@ifclear PRINTF_COMMAND
+@item \\0@var{nnn}
 the eight-bit value that is the octal number @var{nnn}
 (zero to three octal digits), if @var{nnn} is
 a nine-bit value, the ninth bit is ignored
-@item \@var{nnn}
+@end ifclear
+@item \\@var{nnn}
 the eight-bit value that is the octal number @var{nnn}
 (one to three octal digits), if @var{nnn} is
 a nine-bit value, the ninth bit is ignored
-@item \x@var{hh}
+@item \\x@var{hh}
 the eight-bit value that is the hexadecimal number @var{hh}
 (one or two hexadecimal digits)
+@ifset PRINTF_COMMAND
+@item \\u@var{hhhh}
+Unicode (ISO/IEC 10646) character with hex value HHHH (4 digits)
+@item \\U@var{hhhhhhhh}
+Unicode character with hex value HHHHHHHH (8 digits)
+@end ifset
 @end table
+@end macro
+@escapeSequences
 
 @optItem{echo,-E,}
 @cindex backslash escapes
@@ -12950,10 +12965,18 @@ in a way that is mostly similar to the C @samp{printf} function,
 and C language escape sequence processing.
 @xref{Output Conversion Syntax,, @command{printf} format directives,
 libc, The GNU C Library Reference Manual}, for details.
-See also @uref{https://en.cppreference.com/w/c/language/escape,
-C99 string escapes:}.
 
-Examples of supported conversion specifiers and flags are:
+@mayConflictWithShellBuiltIn{printf}
+
+Supported escape sequences are:
+
+@indentedblock
+@set PRINTF_COMMAND
+@escapeSequences
+@clear PRINTF_COMMAND
+@end indentedblock
+
+Supported conversion specifiers with examples are:
 
 @example
 CONVERSION  Shell format example        Output
@@ -12975,8 +12998,6 @@ CONVERSION  Shell format example        Output
 %q          '%q ' 'a' ';b' $'c\n'       a ';b' 'c'$'\n'
 @end example
 
-@mayConflictWithShellBuiltIn{printf}
-
 The differences from the C @samp{printf} function are:
 
 @itemize @bullet