Re: Problem with pattern replacing when STRING is an expandable char
Mike Stroyan wrote:
Repeat-By:
a=111.1
echo ${a//[0-9]/x}
correctly gives "xxx.x", but
echo ${a//[0-9]/*}
gives a listing of files in current directory. Seems that the "*"
is expanded before replacing the pattern.
It workes the right way at least up to bash-3.1.17(1)-release
But if you set
a=111
it doesn't even work in 3.1.17 right.
The pathname expansion of "*" is not done until after the parameter
expansion substitution. That is the documented behavior. The following
example shows that echo of the "***.*" pattern matches files and
directories that have a "." in their name. Setting a to "111" results
in a pathname pattern of "***" that matches all of the files.
Double quoting the substitution prevents pathname expansion.
$ echo $BASH_VERSION
3.2.25(1)-release
$ touch a b c.d e.f
$ ls
a b c.d e.f
$ a=111.1
$ echo ${a//[0-9]/*}
c.d e.f
$ echo "${a//[0-9]/*}"
***.*
$ a=111
$ echo ${a//[0-9]/*}
a b c.d e.f
$ echo "${a//[0-9]/*}"
***
$
Thanks a lot for your fast response! Ok, even after so many years
bash is astounding if you don't have all expansion rules in mind
every time.
Kind regards,
Ado
Re: Problem with pattern replacing when STRING is an expandable char
Paul Jarc wrote:
Heinz-Ado Arnolds <[EMAIL PROTECTED]> wrote:
a=111.1
echo ${a//[0-9]/x}
correctly gives "xxx.x", but
echo ${a//[0-9]/*}
gives a listing of files in current directory. Seems that the "*"
is expanded before replacing the pattern.
No, it's expanded afterward, because the variable expansion isn't
quoted. This does what you want:
echo "${a//[0-9]/*}"
It workes the right way at least up to bash-3.1.17(1)-release
But if you set
a=111
it doesn't even work in 3.1.17 right.
3.1.17 behaves the same way as 3.2.25. You see a different result
because of a different set of files between the two situations, not
because of the different bash version. If there are no files in the
current directory that match ***.*, then pathname expansion will leave
it unchanged.
paul
Thanks a lot for your fast response! Ok, even after so many years
bash is astounding if you don't have all expansion rules in mind
every time.
Kind regards,
Ado
Re: Problem with pattern replacing when STRING is an expandable char
>
> Repeat-By:
> a=111.1
> echo ${a//[0-9]/x}
>
> correctly gives "xxx.x", but
>
> echo ${a//[0-9]/*}
>
> gives a listing of files in current directory. Seems that the "*"
> is expanded before replacing the pattern.
>
> It workes the right way at least up to bash-3.1.17(1)-release
>
> But if you set
>
> a=111
>
> it doesn't even work in 3.1.17 right.
The pathname expansion of "*" is not done until after the parameter
expansion substitution. That is the documented behavior. The following
example shows that echo of the "***.*" pattern matches files and
directories that have a "." in their name. Setting a to "111" results
in a pathname pattern of "***" that matches all of the files.
Double quoting the substitution prevents pathname expansion.
$ echo $BASH_VERSION
3.2.25(1)-release
$ touch a b c.d e.f
$ ls
a b c.d e.f
$ a=111.1
$ echo ${a//[0-9]/*}
c.d e.f
$ echo "${a//[0-9]/*}"
***.*
$ a=111
$ echo ${a//[0-9]/*}
a b c.d e.f
$ echo "${a//[0-9]/*}"
***
$
--
Mike Stroyan <[EMAIL PROTECTED]>
Re: Problem with pattern replacing when STRING is an expandable char
Heinz-Ado Arnolds <[EMAIL PROTECTED]> writes:
> Repeat-By:
> a=111.1
> echo ${a//[0-9]/x}
>
> correctly gives "xxx.x", but
>
> echo ${a//[0-9]/*}
>
> gives a listing of files in current directory.
Only those that contain a period.
> Seems that the "*"
> is expanded before replacing the pattern.
No, it is expanded afterwards, since filename expansion is carried out
after parameter expansion. You need to quote it properly.
Andreas.
--
Andreas Schwab, SuSE Labs, [EMAIL PROTECTED]
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."
Re: Problem with pattern replacing when STRING is an expandable char
Heinz-Ado Arnolds <[EMAIL PROTECTED]> wrote:
> a=111.1
> echo ${a//[0-9]/x}
>
> correctly gives "xxx.x", but
>
> echo ${a//[0-9]/*}
>
> gives a listing of files in current directory. Seems that the "*"
> is expanded before replacing the pattern.
No, it's expanded afterward, because the variable expansion isn't
quoted. This does what you want:
echo "${a//[0-9]/*}"
> It workes the right way at least up to bash-3.1.17(1)-release
>
> But if you set
>
> a=111
>
> it doesn't even work in 3.1.17 right.
3.1.17 behaves the same way as 3.2.25. You see a different result
because of a different set of files between the two situations, not
because of the different bash version. If there are no files in the
current directory that match ***.*, then pathname expansion will leave
it unchanged.
paul
Problem with pattern replacing when STRING is an expandable char
Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i686'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I/tmp/S/bash-3.2 -I/tmp/S/bash-3.2/include
-I/tmp/S/bash-3.2/lib -g -O2
uname output: Linux * 2.6.23.1 #1 SMP PREEMPT Tue Oct 16 16:47:14 CEST
2007 i686 GNU/Linux
Machine Type: i686-pc-linux-gnu
Bash Version: 3.2
Patch Level: 25
Release Status: release
Description:
Pattern replacing doesn't work like documented with special
characters "*" and "?" as replacment strings
Repeat-By:
a=111.1
echo ${a//[0-9]/x}
correctly gives "xxx.x", but
echo ${a//[0-9]/*}
gives a listing of files in current directory. Seems that the "*"
is expanded before replacing the pattern.
It workes the right way at least up to bash-3.1.17(1)-release
But if you set
a=111
it doesn't even work in 3.1.17 right.
Kind regards,
H.-A. Arnolds
--
Dipl.-Ing. Heinz-Ado Arnolds
MPI fuer Astrophysik
Karl-Schwarzschild-Strasse 1
D-85748 Garching
Phone: +49/89/3-2217
FAX : +49/89/3-2388
email: arnolds[at]MPA-Garching.MPG.DE
