Re: command substitution and word splitting

[Andreas Schwab]

S. Sevki Dincer jfcga...@gmail.com writes:

 i want to start building a project with ./configure --prefix=... $(myflags)
 where myflags is an executable text file on my path. myflags has the
 following in it:
 printf 'CFLAGS=-O2 -fomit-frame-pointer '
 printf 'LDFLAGS=-Wl,-O2'
 now, when i do that ./configure complains for not recognizing
 -fomit-frame-pointer option, and actually word splitting of bash ruins
 what i wanna do. i want the word splitting of a command substitution
 to be careful about the quotes in the resulting expansion. is that
 possible?

Use eval.

eval ./configure --prefix=... $(myflags)

Andreas.

-- 
Andreas Schwab, SuSE Labs, sch...@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
And now for something completely different.

echo $s{2,3}

[jidanni]

What happened to 2,3? Poof, gone.
$ s=a; echo $s{ $s{} $s} $s{1} $s{2,3} ${s}{4,5}
a{ a{} a} a{1} a4 a5

Re: echo $s{2,3}

[Bernd Eggink]

jida...@jidanni.org schrieb:

What happened to 2,3? Poof, gone.
$ s=a; echo $s{ $s{} $s} $s{1} $s{2,3} ${s}{4,5}
a{ a{} a} a{1} a4 a5


As the manual says, brace expansion is performed before any other 
expansions. So $s{2,3} expands to $s2 $s3, and that expands to nothing 
if neither s2 nor s3 are set.


Regards,
Bernd

--
Bernd Eggink
http://sudrala.de

Re: command substitution and word splitting

[Stephane Chazelas]

On Sat, Dec 13, 2008 at 09:30:27AM +0100, Andreas Schwab wrote:
 S. Sevki Dincer jfcga...@gmail.com writes:
 
  i want to start building a project with ./configure --prefix=... $(myflags)
  where myflags is an executable text file on my path. myflags has the
  following in it:
  printf 'CFLAGS=-O2 -fomit-frame-pointer '
  printf 'LDFLAGS=-Wl,-O2'
  now, when i do that ./configure complains for not recognizing
  -fomit-frame-pointer option, and actually word splitting of bash ruins
  what i wanna do. i want the word splitting of a command substitution
  to be careful about the quotes in the resulting expansion. is that
  possible?
 
 Use eval.
 
 eval ./configure --prefix=... $(myflags)
[...]

eval ./configure --prefix=... $(myflags)

as you don't want word splitting nor filename generation in this
case.

You could also have done:

printf 'CFLAGS=-O2 -fomit-frame-pointer|'
printf 'LDFLAGS=-Wl,-O2'

and then:

IFS='|'
set -f
./configure --prefix=... $(myflags)

Or:

cat  EOF
CFLAGS=-O2 -fomit-frame-pointer
LDFLAGS=-Wl,-O2
EOF

and then:

IFS='
'
set -f
./configure --prefix=... $(myflags)

-- 
Stéphane