Re: String substitution bug
On Monday, November 25th, 2024 at 5:49 PM, Chet Ramey wrote: > On 11/23/24 9:29 PM, marcel.plch via Bug reports for the GNU Bourne Again > SHell wrote: > > > Thank you for clarifictaion. > > > > Maybe adding an extra clarification to the bash manpage > > in the Pattern Matching section would be a good idea? > > > I can add some clarifying text, but I figure that the since this text > appears in the section describing [...] bracket expressions that it > would have been reasonable to infer that it describes how pattern > matching treats characters between those brackets, and that if the > description of, say, character classes includes additional brackets, > then those are required. Not in one place the pattern "[[:space:]]" is mentioned. I understand that the current formulation of the manpage sounds rather obvious to you (it does to me as well now that I get it), but when reading it for the first time, I thought that the "between [ and ]" part is speaking of the brackets already contained within the "[:space:]" expression and that the check of whether or not this is a class is based on the fact that the expression has the first brace followed by a colon and the second brace lead by a colon. This small assumption lead me to losing a whole evening pulling my hair out and 3 (three!) points of reputation on Stackoverflow [0]. If adding just one sentence containing "[[:space:]]" to clarify the section a tiny bit more, I think that it is well worth it. [0] - https://stackoverflow.com/questions/79219041/bash-string-substitution-bug -- Dormouse publickey - marcel.plch@proton.me - 0x1094A451.asc Description: application/pgp-keys signature.asc Description: OpenPGP digital signature
String substitution bug
Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -march=x86-64 -mtune=generic -O2 -pipe -fno-plt
-fexceptions -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security
-fstack-clash-protection -fcf-protection -fno-omit-frame-pointer
-mno-omit-leaf-frame-pointer -g
-ffile-prefix-map=/build/bash/src=/usr/src/debug/bash -flto=auto
-DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin'
-DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc'
-DSYS_BASH_LOGOUT='/etc/bash.bash_logout' -DNON_INTERACTIVE_LOGIN_SHELLS
uname output: Linux psappho 6.11.9-arch1-1 #1 SMP PREEMPT_DYNAMIC Sun, 17 Nov
2024 16:06:17 + x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.2
Patch Level: 37
Release Status: release
Description:
I am trying to do some file management in bash and I have strings in this
format:
1 dir/hello.txt
2 dir2/bar.jpg
When I run this substitution:
${FOO/[:space:]*/Hello}
I get this result:
1 dir/hHello
The goal is to substitute everything after the first space (including the
space) with Hello
Seems like a bug to me. In such a case, please confirm and
I will help to investigate
Repeat-By:
Run this shell script:
FOO="1 dir/hello.txt"
echo ${FOO/[:space:]*/Hello}
Thank you for your time
--
Dormouse
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Re: String substitution bug
On Sunday, November 24th, 2024 at 3:05 AM, Lawrence Velázquez
wrote:
> On Sat, Nov 23, 2024, at 7:11 PM, marcel.plch via Bug reports for the GNU
> Bourne Again SHell wrote:
>
> > I am trying to do some file management in bash and I have strings in
> > this format:
> >
> > 1 dir/hello.txt
> > 2 dir2/bar.jpg
> >
> > When I run this substitution:
> > ${FOO/[:space:]*/Hello}
> > I get this result:
> > 1 dir/hHello
> >
> > The goal is to substitute everything after the first space (including
> > the space) with Hello
> >
> > Seems like a bug to me.
>
>
> It is not a bug. Your pattern is incorrect; you should be using
> "[[:space:]]", not "[:space:]". The former is a bracket expression
> containing the character class expression for the "space" character
> class, while the latter is a bracket expression that matches any
> of the characters ":", "s", "p", "a", "c", or "e".
>
> $ FOO='1 dir/hello.txt'
> $ echo "${FOO/[[:space:]]*/Hello}"
> 1Hello
>
> --
> vq
Thank you for clarifictaion.
Maybe adding an extra clarification to the bash manpage
in the Pattern Matching section would be a good idea?
I can imagine I'm not the only one who read this with
a bit of misunderstanding, leading to a few lost hours.
--
Dormouse
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