Re: echo -n

2017-02-06 Thread Stephane Chazelas 
2017-02-06 09:45:26 +0530, Jyoti B Tenginakai:
[...] 
> Again I see that this printf we can use. But there are some scenarios where
> the o/p does not exactly match with echo. So  still its good to have a way
> to pirnt -n /-e/-E with echo. Can this be considered as bug and can this be
> fixed?
[...]

echo -e '\055n' # on ASCII-based systems

echo -e '-n\n\c'

echo -ne '-n\n'

Output "-n" with bash's echo and with the default options.

When in Unix conformance mode (shopt -s xpg_echo; set -o posix)

echo -n

outputs -n followed by a newline character, while

echo '-n\c'

outputs it without the newline character.

All the functionality of echo is available in printf. The %b
format directive has especially been introduced (by POSIX) to
cover for the peculiar style of expansion done by echo (note the
need for \055 instead of \55 like everywhere else) so we have no
excuse to keep using echo.

echo_E() {
  local IFS=' '
  printf '%s\n' "$*"
}

echo_e() {
  local IFS=' '
  printf '%b\n' "$*"
}

echo_nE() {
  local IFS=' '
  printf %s "$*"
}

echo_ne() {
  local IFS=' '
  printf %b "$*"
}

echo is broken. Stop using it.

ksh and zsh introduced a "print" builtin that fixes some of echo
problems (though it still does expansions by default which you
can disable with -r), but bash chose not to implement it, but
does implement the POSIX (though less Unixy in its CLI style)
printf instead.

-- 
Stephane

Re: echo -n

2017-02-05 Thread Peter & Kelly Passchier 
Depending on your use case, you could do something like:
$ echo $'\u2010'n
-n

On 06/02/2560 13:37, Clark Wang wrote:
> On Mon, Feb 6, 2017 at 12:15 PM, Jyoti B Tenginakai
> > wrote:
> 
> Thanks you all,
> 
> Again I see that this printf we can use. But there are some
> scenarios where the o/p does not exactly match with echo. So still
> its good to have a way to pirnt -n /-e/-E with echo. Can this be
> considered as bug and can this be fixed?
> 
> It’s not a bug. According to POSIX.1-2008:
> 
> The |echo| utility shall not recognize the |"--"| argument in the
> manner specified by Guideline 10 of XBD Section 12.2; |"− −"| shall
> be recognized as a string operand.
> 
> It is not possible to use |echo| portably across all POSIX systems
> unless both |−n| (as the first argument) and escape sequences are
> omitted.
> 
> The |echo| utility has not been made obsolescent because of its
> extremely widespread use in historical applications.
> 
> ​

Re: echo -n

2017-02-05 Thread Jyoti B Tenginakai 

Thanks you all,

Again I see that this printf we can use. But there are some scenarios where
the o/p does not exactly match with echo. So  still its good to have a way
to pirnt -n /-e/-E with echo. Can this be considered as bug and can this be
fixed?

Thanks & Regards
--Jyoti


Jyoti Tenginakai
AIX-Security Development Team
IBM India Software Lab
EGD  'D' Block Sixth Floor
Off Indiranagar Koramangala Intermediate Ring Road
Bangaluru - 560071
ph: 4177
extn: 7
Mail:jyoti@in.ibm.com





From:   Chet Ramey <chet.ra...@case.edu>
To: Jyoti B Tenginakai <jyoti@in.ibm.com>, Pierre Gaston
<pierre.gas...@gmail.com>
Cc: chet.ra...@case.edu, Sangamesh Mallayya
<sangamesh.sw...@in.ibm.com>, "bug-bash@gnu.org"
<bug-bash@gnu.org>
Date:   02/02/2017 11:21 PM
Subject:Re: echo -n



On 2/2/17 11:56 AM, Jyoti B Tenginakai wrote:
> HI All,
>
> Thanks for your quick response.
>
> I have tried using the printf instead of echo. But the issue with printf
is
> , the behaviour is not consistent with what echo prints for all the
inputs
> i.e.
> In my script I am generically using echo for all the options. If I have
to
> use printf instead of it should behave consistently .
> if echo * is passed to bash shell, the o/p shows the \t seperated values
> whereas with printf '%s' *, it won't display space separated output.
Again
> printf '%s ' # behaviour is different from what echo # shows

echo()
{
 builtin printf "%s\n" "$*"
}

You can make this more elaborate if you want.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
  ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRUc...@case.edu
http://cnswww.cns.cwru.edu/~chet/

Re: echo -n

2017-02-02 Thread Stephane Chazelas 
2017-02-02 22:26:22 +0530, Jyoti B Tenginakai:
[...]
> I have tried using the printf instead of echo. But the issue with printf
> is , the behaviour is not consistent with what echo prints for all the
> inputs i.e.
> In my script I am generically using echo for all the options. If I have to
> use printf instead of it should behave consistently .
> if echo * is passed to bash shell, the o/p shows the \t seperated values
> whereas with printf '%s'  *, it won't display space separated output. Again
> printf '%s ' # behaviour is different from what echo # shows
[...]

See also:

https://unix.stackexchange.com/questions/65803/why-is-printf-better-than-echo


In bash, you can define:

puts() {
  local IFS=' '
  printf '%s\n' "$*"
}

as a function that outputs its arguments separated by spaces and
terminated with a newline character.

POSIXly:

puts() (
  IFS=' '
  printf '%s\n' "$*"
)

With with some shells like bash, that implies an additional
fork.

Note hat ksh and zsh also have:

print -r -- *

for that.

-- 
Stephane

Re: echo -n

2017-02-02 Thread Chet Ramey 
On 2/2/17 11:56 AM, Jyoti B Tenginakai wrote:
> HI All,
> 
> Thanks for your quick response.
> 
> I have tried using the printf instead of echo. But the issue with printf is
> , the behaviour is not consistent with what echo prints for all the inputs
> i.e.
> In my script I am generically using echo for all the options. If I have to
> use printf instead of it should behave consistently .
> if echo * is passed to bash shell, the o/p shows the \t seperated values
> whereas with printf '%s' *, it won't display space separated output. Again
> printf '%s ' # behaviour is different from what echo # shows

echo()
{
builtin printf "%s\n" "$*"
}

You can make this more elaborate if you want.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRUc...@case.eduhttp://cnswww.cns.cwru.edu/~chet/

Re: echo -n

2017-02-02 Thread John McKown 
On Thu, Feb 2, 2017 at 10:56 AM, Jyoti B Tenginakai <jyoti@in.ibm.com>
wrote:

> HI All,
>
> Thanks for your quick response.
>
> I have tried using the printf instead of echo. But the issue with printf
> is , the behaviour is not consistent with what echo prints for all the
> inputs i.e.
> In my script I am generically using echo for all the options. If I have to
> use printf instead of it should behave consistently .
> if echo * is passed to bash shell, the o/p shows the \t seperated values
> whereas with printf '%s' *, it won't display space separated output. Again
> printf '%s ' # behaviour is different from what echo # shows
>
​Yes, it is. You can change the output by using the appropriate "format"
(the '%s' in your example). For example:

echo -n *

could be emulated with:

printf '%s ' * #note the space in the format after the %s

The outputs are not _identical_ because the printf output has a trailing
space, which the echo does not.​ If you want tab separators, try:

printf '%s\t' *

​If you want something which 100.% works exactly and identically like
the BASH "echo" builtin, then you are doomed to disappointment. If you want
a replacement for "echo -n", you might try using a function (defined in
~/.bashrc) similar to:

function echo-n() { printf '%s ' "$@" | sed -r 's/ $//'; }​

>
> Thanks & Regards
> --Jyoti
>
> --
There’s no obfuscated Perl contest because it’s pointless.

—Jeff Polk

Maranatha! <><
John McKown

Re: echo -n

2017-02-02 Thread Greg Wooledge 
On Thu, Feb 02, 2017 at 10:26:22PM +0530, Jyoti B Tenginakai wrote:
> I have tried using the printf instead of echo. But the issue with printf
> is , the behaviour is not consistent with what echo prints for all the
> inputs i.e.

But what echo prints is by definition inconsistent across platforms and
shells and so on.

Make the code do what you want.  Do not attempt to make it use a broken
command in some consistent way.

> In my script I am generically using echo for all the options.

Why?  What do you want to write to stdout?  Figure out what you want to
do, then do it.

> If I have to
> use printf instead of it should behave consistently .

printf behaves consistently.

> if echo * is passed to bash shell

... what does that mean?  Your user is passing a quoted string 'echo *'
as an argument?  What are you doing, eval'ing user arguments as shell
commands?

Or do you mean that you have the command   echo *   in your script?

What do you WANT it to do?

Do you want it to print the files in $PWD one per line?  Blithely ignoring
the possibility of filenames that contain newlines?

printf '%s\n' *

That will print each filename (except dot files, but your original command
has the same issue) with a newline after it.

If a filename contains a newline, then there will be two newlines
produced for that particular filename: the one inside it, and the one
added by the printf format spec.

> the o/p shows the \t seperated values

The who what?  What the hell are you talking about now?

> whereas with printf '%s'  *, it won't display space separated output.

You want SPACES now?

printf '%s ' *

> Again
> printf '%s ' # behaviour is different from what echo # shows

Are you talking aobut the one trailing space that you'll get from

printf '%s ' *

vs.

echo *

??

Do you actually CARE about ONE SPACE?

Do you have an actual GOAL here?  Or are you just flailing around
randomly until you stumble across some way to bitch about printf?

I really hate it when people have a desired answer and then keep
flailing around at the English language until they come up with a
question that they think will give them their desired answer.

In your case, your desired answer is apparently "to run the command echo *".

Nobody can possibly satisfy your demands, because you don't have a goal.

Re: echo -n

2017-02-02 Thread Jyoti B Tenginakai 

HI All,

Thanks for your quick response.

I have tried using the printf instead of echo. But the issue with printf
is , the behaviour is not consistent with what echo prints for all the
inputs i.e.
In my script I am generically using echo for all the options. If I have to
use printf instead of it should behave consistently .
if echo * is passed to bash shell, the o/p shows the \t seperated values
whereas with printf '%s'  *, it won't display space separated output. Again
printf '%s ' # behaviour is different from what echo # shows

Thanks & Regards
--Jyoti



Jyoti Tenginakai
AIX-Security Development Team
IBM India Software Lab
EGD  'D' Block Sixth Floor
Off Indiranagar Koramangala Intermediate Ring Road
Bangaluru - 560071
ph: 4177
extn: 7
Mail:jyoti@in.ibm.com





From:   Pierre Gaston <pierre.gas...@gmail.com>
To: Sangamesh Mallayya <sangamesh.sw...@in.ibm.com>
Cc: "bug-bash@gnu.org" <bug-bash@gnu.org>, Jyoti B Tenginakai
<jyoti@in.ibm.com>
Date:   02/02/2017 08:45 PM
Subject:Re: echo -n





On Thu, Feb 2, 2017 at 11:02 AM, Sangamesh Mallayya <
sangamesh.sw...@in.ibm.com> wrote:
  Hi,

  description:
  in bash echo -n , echo -e , echo -E has a special meaning. But we do not
  have a way in bash shell if we want to print
  -n , -e and -E using echo command. Other shells supports printing of
  -n/-e/-E options using echo command.

  For example

  with ksh
  # echo -n
  -n
  #

  with bash
  # echo -n

  #

  Please let us know if this a bug or do we have any other option to print
  -n ?

  Here is the environment details.

  version: bash 4.3
  Hardware and Operating System P7 AIX
  Compiled with AIX xlc

  Thanks,
  -Sangamesh




Not a bug, echo is not portable and posix recommends using printf e.g.

printf '%s\n' -n

Re: echo -n

2017-02-02 Thread Eduardo Bustamante 
El jue., feb. 2, 2017 9:00 AM, Sangamesh Mallayya <
sangamesh.sw...@in.ibm.com> escribió:

> [...]
>
> Please let us know if this a bug or do we have any other option to print
> -n ?
>

Use the printf builtin command. What you encountered is a known limitation
of the echo command, as specified by POSIX.

Re: echo -n

2017-02-02 Thread Pierre Gaston 
On Thu, Feb 2, 2017 at 11:02 AM, Sangamesh Mallayya <
sangamesh.sw...@in.ibm.com> wrote:

> Hi,
>
> description:
> in bash echo -n , echo -e , echo -E has a special meaning. But we do not
> have a way in bash shell if we want to print
> -n , -e and -E using echo command. Other shells supports printing of
> -n/-e/-E options using echo command.
>
> For example
>
> with ksh
> # echo -n
> -n
> #
>
> with bash
> # echo -n
>
> #
>
> Please let us know if this a bug or do we have any other option to print
> -n ?
>
> Here is the environment details.
>
> version: bash 4.3
> Hardware and Operating System P7 AIX
> Compiled with AIX xlc
>
> Thanks,
> -Sangamesh
>
>
>
>
Not a bug, echo is not portable and posix recommends using printf e.g.

printf '%s\n' -n

Re: echo -n

2017-02-02 Thread John McKown 
On Thu, Feb 2, 2017 at 3:02 AM, Sangamesh Mallayya <
sangamesh.sw...@in.ibm.com> wrote:

> Hi,
>
> description:
> in bash echo -n , echo -e , echo -E has a special meaning. But we do not
> have a way in bash shell if we want to print
> -n , -e and -E using echo command. Other shells supports printing of
> -n/-e/-E options using echo command.
>
> For example
>
> with ksh
> # echo -n
> -n
> #
>
> with bash
> # echo -n
>
> #
>
> Please let us know if this a bug or do we have any other option to print
> -n ?
>

​Well, as another told me "echo is _evil_". You could use "printf" instead:

$ printf '%s\n' '-n'
-n



-- 
There’s no obfuscated Perl contest because it’s pointless.

—Jeff Polk

Maranatha! <><
John McKown

Re: echo -n

2017-02-02 Thread Greg Wooledge 
On Thu, Feb 02, 2017 at 02:32:00PM +0530, Sangamesh Mallayya wrote:
> in bash echo -n , echo -e , echo -E has a special meaning. But we do not 
> have a way in bash shell if we want to print 
> -n , -e and -E using echo command. Other shells supports printing of 
> -n/-e/-E options using echo command. 

Use printf instead of echo.

printf '%s\n' "$myvariable"

This will work regardless of the contents of the variable.

echo is deprecated, and should not be used unless you are certain that
it will not be given an argument that could be misinterpreted as an
option.

E.g. this is fine:

echo "You scored $points points."

This is not fine:

echo "$foo"

This was NEVER acceptable and you should not even THINK it:

echo $foo

echo -n

2017-02-02 Thread Sangamesh Mallayya 
Hi,

description: 
in bash echo -n , echo -e , echo -E has a special meaning. But we do not 
have a way in bash shell if we want to print 
-n , -e and -E using echo command. Other shells supports printing of 
-n/-e/-E options using echo command. 

For example 

with ksh 
# echo -n
-n
#

with bash
# echo -n

#

Please let us know if this a bug or do we have any other option to print 
-n ?

Here is the environment details.

version: bash 4.3
Hardware and Operating System P7 AIX
Compiled with AIX xlc

Thanks,
-Sangamesh

Why `echo -n hello | while read v; do echo $v; done' prints nothing?

2010-12-02 Thread Clark J. Wang 
Following command also prints nothing, confused :(

for ((i = 0; i  10; ++i)); do echo -n  $i; done | while read v; do echo
$v; done

-- 
Clark

Re: Why `echo -n hello | while read v; do echo $v; done' prints nothing?

2010-12-02 Thread William Park 
On Thu, Dec 02, 2010 at 11:33:24AM -0500, Greg Wooledge wrote:
 On Thu, Dec 02, 2010 at 09:29:29AM -0700, Eric Blake wrote:
  On 12/02/2010 04:04 AM, Clark J. Wang wrote:
   Following command also prints nothing, confused :(
   
   for ((i = 0; i  10; ++i)); do echo -n  $i; done | while read v; do echo
   $v; done
  
  http://www.faqs.org/faqs/unix-faq/shell/bash/
  FAQ E4.
 
 That was my first thought as well, upon first glance.  But that's not
 the actual problem here.  It's the lack of newline causing read to return
 'failure' even though it does read the input.

Yeah, it has bitten me too many times.  I keep forgetting it though.

-- 
William

Re: Why `echo -n hello | while read v; do echo $v; done' prints nothing?

2010-12-02 Thread Clark J. Wang 
On Thu, Dec 2, 2010 at 11:49 PM, Greg Wooledge wool...@eeg.ccf.org wrote:

 On Thu, Dec 02, 2010 at 07:04:57PM +0800, Clark J. Wang wrote:
  Following command also prints nothing, confused :(
 
  for ((i = 0; i  10; ++i)); do echo -n  $i; done | while read v; do
 echo
  $v; done

 The output from the first command in the pipeline does not end with a
 newline.  Therefore, 'read' in the second command returns 'failure'
 (non-zero) when it reads the first line of input, and your loop never
 iterates.


But is that reasonable? I think read should return success in this case
which makes more sense to me. Does the POSIX standards require that?

-- 
Clark

Re: Why `echo -n hello | while read v; do echo $v; done' prints nothing?

2010-12-02 Thread Eric Blake 
On 12/02/2010 07:02 PM, Clark J. Wang wrote:
 The output from the first command in the pipeline does not end with a
 newline.  Therefore, 'read' in the second command returns 'failure'
 (non-zero) when it reads the first line of input, and your loop never
 iterates.
 
 But is that reasonable? I think read should return success in this case
 which makes more sense to me. Does the POSIX standards require that?

POSIX requires that the input to read be a text file (and by the
definition of text file in POSIX, it must either be empty or end in a
newline).  By violating POSIX and passing something that does not end in
a newline, you are no longer bound by the rules of POSIX.  Therefore, it
would be a reasonable bash extension that read could return 0 status if
it read data that did not end in a newline, but it would not be a
standard-compliant script that relied on such an extension.  You're
better off supplying the trailing newline, and guaranteeing a compliant
usage.

-- 
Eric Blake   ebl...@redhat.com+1-801-349-2682
Libvirt virtualization library http://libvirt.org



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Re: [bash 3.1.5] sh -c echo -n ok broken

2006-01-19 Thread Chet Ramey 
 So, it is possible to have both the following working in sh and bash
 
   echo -n ok
   echo ok\c

No.  In posix mode, they are fundamentally incompatible.  The combination of
posix mode and xpg-echo cause bash to be strictly posix compliant and disable
any option processing.

This is item `c' in the New Features section of NEWS.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet )
Live Strong.
Chet Ramey, ITS, CWRU[EMAIL PROTECTED]http://tiswww.tis.case.edu/~chet/


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Re: [bash 3.1.5] sh -c echo -n ok broken

2006-01-18 Thread Mike Frysinger 
On Wednesday 18 January 2006 18:34, Jeff Chua wrote:
 GNU bash, version 3.1.5(1)-release

 sh -c echo -n ok returns -n ok.

works correctly for me:
[EMAIL PROTECTED] 0 ~ $ sh -c echo -n ok 
[EMAIL PROTECTED] 0 ~ $ 
-mike


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Re: [bash 3.1.5] sh -c echo -n ok broken

2006-01-18 Thread Chet Ramey 
Jeff Chua wrote:
 
 GNU bash, version 3.1.5(1)-release
 
 sh -c echo -n ok returns -n ok.
 
 This breaks a lot of scripts ... startup scripts in /etc/rc.d and many
 packages like glibc make check that use sh instead of bash with
 -n option.
 
 How can I make sh -c echo -n ok returns ok instead -n ok?
 
 I've tried compiling with --disable-strict-posix-default but that
 doesn't work.

It doesn't behave that way by default:

z3.local(1)$ ./sh --version
GNU bash, version 3.1.5(2)-release (powerpc-apple-darwin8.3.0)
Copyright (C) 2005 Free Software Foundation, Inc.
z3.local(1)$ ./sh -c 'echo -n ok'
okz3.local(1)$

Somehow you've enabled the xpg_echo option, either by configuring
with --enable-xpg-echo-default or running `shopt -s xpg_echo'
somewhere.  I suspect the former.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet )
Live Strong.
Chet Ramey, ITS, CWRU[EMAIL PROTECTED]http://cnswww.cns.cwru.edu/~chet/


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[bash 3.1.5] sh -c echo -n ok broken

2006-01-18 Thread Jeff Chua 


GNU bash, version 3.1.5(1)-release

sh -c echo -n ok returns -n ok.

This breaks a lot of scripts ... startup scripts in /etc/rc.d and many 
packages like glibc make check that use sh instead of bash with -n 
option.


How can I make sh -c echo -n ok returns ok instead -n ok?

I've tried compiling with --disable-strict-posix-default but that doesn't 
work.



Thanks,
Jeff


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Re: [bash 3.1.5] sh -c echo -n ok broken

2006-01-18 Thread Jeff Chua 

On Wed, 18 Jan 2006, Chet Ramey wrote:


Somehow you've enabled the xpg_echo option, either by configuring
with --enable-xpg-echo-default or running `shopt -s xpg_echo'
somewhere.  I suspect the former.


Yes, I did --enable-xpg-echo-default as I need echo ok\c to work.

The older bash-3.00.15(3) works with --enable-xpg-echo-default.


So, it is possible to have both the following working in sh and bash

echo -n ok
echo ok\c

Thanks,
Jeff.




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Re: [bash 3.1.5] sh -c echo -n ok broken

2006-01-18 Thread Chris F.A. Johnson 

On Thu, 19 Jan 2006, Jeff Chua wrote:


On Wed, 18 Jan 2006, Chet Ramey wrote:


Somehow you've enabled the xpg_echo option, either by configuring
with --enable-xpg-echo-default or running `shopt -s xpg_echo'
somewhere.  I suspect the former.


Yes, I did --enable-xpg-echo-default as I need echo ok\c to work.

The older bash-3.00.15(3) works with --enable-xpg-echo-default.


So, it is possible to have both the following working in sh and bash

echo -n ok
echo ok\c


printf %s ok

--
   Chris F.A. Johnson  http://cfaj.freeshell.org
   ===
   Author:
   Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)


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