2, the regular expression of one of the advanced _

#!/usr/bin/perlforeach $var(Glob("*.wav")){        #$var =~/.* (00.*). wav/;        $var=~ /.*(xx\d\d). wav/; $Newvar='spkcontext_zj_'.$1.'. wav'; system("MV $var $Newvar"); Print "Now is processing $var \ n";}Print "Over \ n";

1. To use a more accurate regular expression, do not use fuzzy regular expressions:
   1. For example, the file name is as follows:spkcontext_0001.wav
   2. We're going to capture, where 0001 of these 4 strings (or maybe called numbers), I now have two ways of writing:

      1. $var =~/.* (xx. *). wav/;

      2. $var =~/.* (xx\d\d). wav/;

   3. The above two types of writing, of course, the second one is more specific, more accurate.
   4. In the first form, the question that arises is:
      
      1. The captured variable has a value of 001, not 0001
      2. The second way of writing does not occur.

2, the regular expression of one of the advanced _