The answer is in the part you neglected to read.
NULL can be passed to function only "escaped"
\0
\x00
but $'\x00' is not like "\x00", because the first is expanded "before",
and the second is expanded "after"
$ printf $'\x00'
+-+-+-+-+-+-+--+ +--+--+
|p|r|i|n|t|f|\0| |\0|\0|
+-+-+-+-+-
Antonio Macchi wrote:
> but...
>
> $ printf one$'\x00'two\\n
>
> +-+-+-+-+-+-+--+
> |p|r|i|n|t|f|\0|
> +-+-+-+-+-+-+--+
>
> +-+-+-+--+-+-+-+--+--+
> |o|n|e|\0|t|w|o|\n|\0|
> +-+-+-+--+-+-+-+--+--+
>
> so the output should be "one", and stop here!
>
> but the real output is
> onetwo
>
> so, i
Antonio Macchi wrote:
>> $ printf "\x00\n" | cat -A
>> ^@
>
> it works, so why...
>
> $ printf $'\x00' | cat -A
> $
Read carefully ALL the answers you've been given. The short version is that
$'\x00' is interpreted by bash itself, while '\x00\n' is interpreted by
printf only. But DO READ the
On 25 Nov 2009, at 16:27, Antonio Macchi wrote:
>> imadev:~$ echo $'foo\0bar'
>> foo
>
>
> sorry... I'm a little bit confusing... look
>
> $ echo foo$'\0'bar
> foobar
>
I expect $'\0' expands to the C-string ''. Which then gets added to the
argument after 'foo' and before 'bar'.
When you run read -d $'\x00' what you're really doing is setting up
a bunch of C-strings in memory like this:
+-+-+-+-+--+-
|r|e|a|d|\0|
+-+-+-+-+--+-
+-+-+--+-
|-|d|\0|
+-+-+--+-
+--+--+-
|\0|\0|
+--+--+-
WOW!
but...
$ printf one$'\x00'two\\n
+-+-+-+-+-+-+--+
|p|r|i|n|t|f|\0|
Antonio Macchi writes:
>> $ printf "\x00\n" | cat -A
>> ^@
>
> it works, so why...
>
> $ printf $'\x00' | cat -A
> $
>
> ... not?
The answer is in the part you neglected to read.
Andreas.
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8
$ printf "\x00\n" | cat -A
^@
it works, so why...
$ printf $'\x00' | cat -A
$
... not?
On Wed, Nov 25, 2009 at 02:35:51PM +0100, Antonio Macchi wrote:
> it sounds strange, beacuse
>
> $ find . -print0 | while read -d $'\x00'; do touch "$REPLY"; done
>
> works fine.
>
>
> but if I try to "output" $'\x00', I can't.
There's a lot going on here, so I'll try to cover it as best I can
On 25 Nov 2009, at 14:58, Antonio Macchi wrote:
> my goal is very very stupid, like this
>
> $ printf "%q" $(
> to get a "ascii form" of a binary file (something like uuencode)
>
>
> but, as you can see, it does not work only for two binary chars
>
> 0x00, and 0x0a
That doesn't sound like a
Antonio Macchi writes:
> but, as you can see, it does not work only for two binary chars
The argument space is not suitable for binary I/O.
Andreas.
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something complet
Antonio Macchi writes:
> it sounds strange, beacuse
>
> $ find . -print0 | while read -d $'\x00'; do touch "$REPLY"; done
>
> works fine.
Your "read -d $'\x00'" is exactly equivalent to "read -d ''".
(You should use read -r -d '' to get really unmangled input.)
> but if I try to "output" $'\x00
You can "output" $'\x00' just fine:
$ printf '\0'
Note that -d $'\x00' is the same thing as -d '', for the reason I mentioned
earlier. The argument to the -d option that "read" takes is a C-string.
Understand the difference between *strings* and *streams*. A stream (standard
output of print
(Note blank line in the output -- one newline from the echo command,
and one from the actual content of $myvar.) Using printf -v instead of
x=$(printf) means you don't suffer from the trailing-newline-removal
that command substitution does.
I'm a bit puzzled by the original e-mail, though. I do
> On 25 Nov 2009, at 08:19, Antonio Macchi wrote:
> > Hi, I'm using older bash 3.2.39, so please forgiveme if in your newer bash
> > this issue does not arise.
On Wed, Nov 25, 2009 at 08:25:00AM +0100, Maarten Billemont wrote:
> As for NUL out outputting anything in your result, the cause is C-st
it sounds strange, beacuse
$ find . -print0 | while read -d $'\x00'; do touch "$REPLY"; done
works fine.
but if I try to "output" $'\x00', I can't.
As for NUL out outputting anything in your result, the cause is C-strings.
Arguments are C-strings and those are delimited by NUL bytes. Therefore, the
NUL byte that you're putting in it is actually marking the end of the string.
So the argument ends BEFORE your NUL byte. So it's empty.
As
Hi, I'm using older bash 3.2.39, so please forgiveme if in your newer
bash this issue does not arise.
0x00 and 0x0a has no output in printf "%q"
$ for i in {0..9} a; do printf "%q\n" "`echo -en \"\x0$i\"`"; done
''
$'\001'
$'\002'
$'\003'
$'\004'
$'\005'
$'\006'
$'\a'
$'\b'
$'\t'
''
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