Am 07.05.2012 22:46, schrieb Chet Ramey:
> On 5/3/12 5:53 AM, Ruediger Kuhlmann wrote:
>> Hi,
>>
>> please try the following bash script:
>>
>> a=x
>> del="$(echo -e "\\x7f")"
>>
>> echo "$del${a#x}" | od -ta
>> echo "$del ${a#x}" | od -ta
>> echo " $del${a#x}" | od -ta
>>
>> Using bash 3.2, the output is:
>>
>> 0000000 del nl
>> 0000002
>> 0000000 del sp nl
>> 0000003
>> 0000000 sp del nl
>> 0000003
>>
>> however with bash 4.1 and bash 4.2.20, the output is only:
>>
>> 0000000 del nl
>> 0000002
>> 0000000 sp nl
>> 0000002
>> 0000000 sp nl
>> 0000002
>>
>> ... so in the second and third line, the delete character magically
>> disappears. Neither OS nor locale seem to influence this. Using a delete
>> character directly in the script instead of $del also has no impact, either.
> It's a case of one part of the code violating assumptions made by (and
> conditions imposed by) another. Try the attached patch; it fixes the
> issue for me.
>
> Chet
>
It also works for me.
"$del${a#x}" =[$'\177']
" $del${a%x}" =[$' \177']
" $del""${a:0:0}" =[$' \177']
" ${del}${a:0:0}" =[$' \177']
"${del:0:1}${a#d}" =[$'\177x']
"${del:0:1} ${a#d}" =[$'\177 x']
"${del:0:1} ${a:+}" =[$'\177 ']
"$del ${a#x}" =[$'\177 ']
" $del${a:0:0}" =[$' \177']
" $del${a}" =[$' \177x']
" ${del:0:1}${a:0:0}" =[$' \177']
"${del:0:1}${a#x}" =[$'\177']
"${del:0:1} ${a#x}" =[$'\177 ']
" $del${a#x}" =[$' \177']
" $del"${a:0:0} =[$' \177']
" $del" =[$' \177']
" ${del:0:1}${a}" =[$' \177x']
"${del:0:1} ${a}" =[$'\177 x']
"${del:0:1} ${a:-}" =[$'\177 x']
