If I do

X="my[[:space:]]spc[[:space:]]dir"
echo $X

the output is unexpectedly

my spc dir

but do

X="m[[:space:]]spc[[:space:]]dir"
echo $X

and the output is the expected

m[[:space:]]spc[[:space:]]dir

Indeed, I cannot find any change to my original assignment that leads to
the unexpected behaviour.

Is there some logic behind this, or have I stumbled, completely by
chance, onto some bizarre "easter egg", and thereby lost considerable
time, and some amount of hair?

What the hell.........?

Sylvia.

On 24-Aug-22 1:41 pm, Sylvia Else wrote:
> If I do
>
> X="my[[:space:]]spc[[:space:]]dir"
> echo $X
>
> the output is unexpectedly
>
> my spc dir
>
> but do
>
> X="m[[:space:]]spc[[:space:]]dir"
> echo $X
>
> and the output is the expected
>
> m[[:space:]]spc[[:space:]]dir
>
> Indeed, I cannot find any change to my original assignment that leads to
> the unexpected behaviour.
>
> Is there some logic behind this, or have I stumbled, completely by
> chance, onto some bizarre "easter egg", and thereby lost considerable
> time, and some amount of hair?
>
> What the hell.........?
>
> Sylvia.

OK, seem it's pattern matching against a directory of that name, with
the embedded spaces in its name, which is how this pattern matching
pattern arose in the first place.

All I need to do now is find out where it's documented that it will do
that without being expressly told to.

Sylvia.

On Wed, 24 Aug 2022 13:41:18 +1000
Sylvia Else <sylvia@email.invalid> wrote:
> If I do
>
> X="my[[:space:]]spc[[:space:]]dir"
> echo $X
>
> the output is unexpectedly
>
> my spc dir
[...]

comp.unix.shell is a better place for shell questions.

On 24-Aug-22 2:05 pm, Sylvia Else wrote:
> On 24-Aug-22 1:41 pm, Sylvia Else wrote:
>> If I do
>>
>> X="my[[:space:]]spc[[:space:]]dir"
>> echo $X
>>
>> the output is unexpectedly
>>
>> my spc dir
>>
>> but do
>>
>> X="m[[:space:]]spc[[:space:]]dir"
>> echo $X
>>
>> and the output is the expected
>>
>> m[[:space:]]spc[[:space:]]dir
>>
>> Indeed, I cannot find any change to my original assignment that leads
>> to the unexpected behaviour.
>>
>> Is there some logic behind this, or have I stumbled, completely by
>> chance, onto some bizarre "easter egg", and thereby lost considerable
>> time, and some amount of hair?
>>
>> What the hell.........?
>>
>> Sylvia.
>
> OK, seem it's pattern matching against a directory of that name, with
> the embedded spaces in its name, which is how this pattern matching
> pattern arose in the first place.
>
> All I need to do now is find out where it's documented that it will do
> that without being expressly told to.
>
> Sylvia.

Pathname expansion. Disable by set -f, enable again by set +f

Sylvia Else <sylvia@email.invalid> writes:
> Pathname expansion. Disable by set -f, enable again by set +f

That’s a global setting. The usual approach is to quote all string
expansions except the few where you want pathname expansion.

richard@araminta:~$ x="j*"
richard@araminta:~$ echo $x
junk
richard@araminta:~$ echo "$x"
j*

--
https://www.greenend.org.uk/rjk/

On 24-Aug-22 5:26 pm, Richard Kettlewell wrote:
> Sylvia Else <sylvia@email.invalid> writes:
>> Pathname expansion. Disable by set -f, enable again by set +f
>
> That’s a global setting. The usual approach is to quote all string
> expansions except the few where you want pathname expansion.
>
> richard@araminta:~$ x="j*"
> richard@araminta:~$ echo $x
> junk
> richard@araminta:~$ echo "$x"
> j*
>

Yes. Unfortunately, in this case I need word splitting, just not path
name expansion.

Sylvia.

Sylvia Else <sylvia@email.invalid> writes:
> Richard Kettlewell wrote:
>> Sylvia Else <sylvia@email.invalid> writes:
>>> Pathname expansion. Disable by set -f, enable again by set +f
>> That’s a global setting. The usual approach is to quote all string
>> expansions except the few where you want pathname expansion.
>> richard@araminta:~$ x="j*"
>> richard@araminta:~$ echo $x
>> junk
>> richard@araminta:~$ echo "$x"
>> j*
>>
>
> Yes. Unfortunately, in this case I need word splitting, just not path
> name expansion.

Less weird languages are available...

--
https://www.greenend.org.uk/rjk/

On 24-Aug-22 11:12 pm, Richard Kettlewell wrote:
> Sylvia Else <sylvia@email.invalid> writes:
>> Richard Kettlewell wrote:
>>> Sylvia Else <sylvia@email.invalid> writes:
>>>> Pathname expansion. Disable by set -f, enable again by set +f
>>> That’s a global setting. The usual approach is to quote all string
>>> expansions except the few where you want pathname expansion.
>>> richard@araminta:~$ x="j*"
>>> richard@araminta:~$ echo $x
>>> junk
>>> richard@araminta:~$ echo "$x"
>>> j*
>>>
>>
>> Yes. Unfortunately, in this case I need word splitting, just not path
>> name expansion.
>
> Less weird languages are available...
>

True.

I'm invoking a lot of standard utilities. However, I've come to think
I'd have been better off invoking them from a more conventional
programming languages.

Oh well.

Sylvia.

Sylvia Else <sylvia@email.invalid> wrote:
> If I do
>
> X="my[[:space:]]spc[[:space:]]dir"
> echo $X
>
> the output is unexpectedly
>
> my spc dir

Not for me:

salfter@salfter ~ $ X="my[[:space:]]spc[[:space:]]dir"
salfter@salfter ~ $ echo $X
my[[:space:]]spc[[:space:]]dir

What version of bash are you using? Mine returns this for bash --version:

GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)

This is on Gentoo Linux running in WSL 2 on Win11. Another host running
Gentoo on the metal behaves the same way.

--
_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( https://alfter.us/ Top-posting!
\_^_/ >What's the most annoying thing on Usenet?

On Wed, 24 Aug 2022 15:54:20 +0000, scott wrote:

> Sylvia Else <sylvia@email.invalid> wrote:
>> If I do
>>
>> X="my[[:space:]]spc[[:space:]]dir"
>> echo $X
>>
>> the output is unexpectedly
>>
>> my spc dir
>
> Not for me:
>
> salfter@salfter ~ $ X="my[[:space:]]spc[[:space:]]dir" salfter@salfter ~
> $ echo $X my[[:space:]]spc[[:space:]]dir

I think it's been established that the behaviour is dependent on having
files in the current directory that match the pattern.

--
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
http://www.mirrorservice.org

Bob Eager <news0009@eager.cx> wrote:
> On Wed, 24 Aug 2022 15:54:20 +0000, scott wrote:
>
>> Sylvia Else <sylvia@email.invalid> wrote:
>>> If I do
>>>
>>> X="my[[:space:]]spc[[:space:]]dir"
>>> echo $X
>>>
>>> the output is unexpectedly
>>>
>>> my spc dir
>>
>> Not for me:
>>
>> salfter@salfter ~ $ X="my[[:space:]]spc[[:space:]]dir" salfter@salfter ~
>> $ echo $X my[[:space:]]spc[[:space:]]dir
>
> I think it's been established that the behaviour is dependent on having
> files in the current directory that match the pattern.

Yeah...saw that shortly after I'd posted. That's what happens when you
don't read the whole thread first. :)

--
_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( https://alfter.us/ Top-posting!
\_^_/ >What's the most annoying thing on Usenet?