Iñaki Baz Castillo wrote:

> El Domingo, 14 de Diciembre de 2008, David A. Black escribió:
>> The first thing that comes to mind:
>>
>> text.sub(/(X-Level: )(\*+)/) { $1 + 'X' * $2.size }
>>
>> or, in Oniguruma, using look-behind:
>>
>> text.sub(/(?<=X-Level: )(\*+)/) { 'X' * $1.size }
> 
> Thanks, this is valid in Ruby, but I understand such a operation is
> not feasible with "sed" command, is it?
> I'm not sure yet about if I'll need to do this script in Ruby or
> Shell.
> 
> Thanks a lot.
> 

sed '/^X-Level: /s/\*/X/g'

~]$ echo "X-Level: ****" | sed '/^X-Level: /s/\*/X/g'
X-Level: XXXX
~]$ echo "X-Level: ***********" | sed '/^X-Level: /s/\*/X/g'
X-Level: XXXXXXXXXXX

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