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From: Thomas 'PointedEars' Lahn on 21 Jul 2010 20:31
Kenny McCormack wrote:

> Thomas 'PointedEars' Lahn wrote:
>> Kenny McCormack wrote:
>>> Chris F.A. Johnson <cfajohnson(a)gmail.com> wrote:
>>>> On 2010-07-21, Kenny McCormack wrote:
>>>>> What's the difference between enclosing the cmds in {} vs. ()?
>>>> Commands in ( ) are executed in a subshell.
>>> That's what I thought. So, the answer to the original question, despite
>>> all the other flurry, is simply: Yes, you should use {} rather than ().
>> No, the answer simply is, again, "it depends." That is the part of
>> software development that you do not seem to understand.
>
> You funny.

It was not my intention to amuse you, but to make you think twice. BTW, in
responding like this you are also making a fool of yourself with regard to
grammar.

> (And I've not even seen any pix of you and you funny ears!)

I have not seen a photo of you either. So what?
--
PointedEars
From: Thomas 'PointedEars' Lahn on 22 Jul 2010 05:44
Seebs wrote:

> Thomas 'PointedEars' Lahn wrote:
>> No, the foregone assumption (FGA is not a common Usenet acronym
>
> "Frequently Given Answer", used by some guy whose name I've forgotten
> to refer to things he maintains in a format chosen to prevent people from
> rebutting the idiocy therein.

Thanks. In ten years of regular Usenet participation, in and outside of the
Big 8, I had never come across that acronym. It is not in the Jargon File
either. So I doubt it is more than his original research.

--
PointedEars
From: John DuBois on 22 Jul 2010 11:03
In article <8ap77sFvcrU3(a)mid.individual.net>,
Chris F.A. Johnson <cfajohnson(a)gmail.com> wrote:
>On 2010-07-21, John DuBois wrote:
>> In article <i243tu$l8g$1(a)news.xmission.com>,
>> Kenny McCormack <gazelle(a)shell.xmission.com> wrote:
>>>Workarounds:
>>> 1) append "< /dev/tty" to each command
>>> 2) enclose the commands in parens and redirect that. I.e.:
>>>
>>> commandThatGeneratesTheFilenames | while read x;do
>>> (cmd1;cmd2;cmd3;...) < /dev/tty
>>> done
>>>
>>>Method 2 is nice and seems to work fine, but I am wondering if there is
>>>any hidden cost to it and if there is any more elegant/effcient way to
>>>do this.
>>
>> Unless you specifically want to read from the controlling tty rather than
>> the standard input, it's always better to save the standard input to
>> another fd and then read from it.
>
> Why?

Because the standard input may not be the controlling tty (if the program is
piped or redirected into, or started from an environment with no controlling
tty, etc).

John
--
John DuBois spcecdt(a)armory.com KC6QKZ/AE http://www.armory.com/~spcecdt/
From: Stephane CHAZELAS on 26 Jul 2010 12:57
2010-07-20, 12:13(+00), Kenny McCormack:
> In this group, it is an FGA that one should so:
>
> commandThatGeneratesTheFilenames | while read x ...
>
> instead of the more common:
>
> for i in ...
>
> because of the problems of filenames that spaces and other weird characters.

After

IFS='
' # NL
set -f
for i in $(commandThatGeneratesTheFilenames); do...

shouldn't be a problem (except that the loop only starts when
commandThatGeneratesTheFilenames finishes).

Other solution (not any better either than the ones that have
already been given):

while IFS= read <&3 -r i; do
...
done 3<<EOF
$(commandThatGeneratesTheFilenames)
EOF

{
commandThatGeneratesTheFilenames |
while IFS= read <&3 -r i; do
...
done 3<&0 <&4 4<&-
} 4<&0

as already given would be the best one. If you're picky, you may
write it:

{
commandThatGeneratesTheFilenames 4<&- |
while IFS= read <&3 -r i; do
{
...
} 3<&-
done 3<&0 <&4 4<&-
} 4<&0

or:

{
commandThatGeneratesTheFilenames 4<&- |
while IFS= read -r i 4<&-; do
{
...
} <&4 4<&-
done
} 4<&0

--
Stephane
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