But then you still get warnings?   What I tested with was: 
#!/usr/bin/perl -w

use strict;
use warnings;

my  $var_one;
    $var_one = 'now defined';

sub copy_file {
  while( my $x = <DATA>) {
      $x =~ s|(\$\w+)|$1|eeg; 
      print $x;
  };
}

copy_file();

__DATA__
The variable is $var_one.

[download]
As coded above I get the output 
The variable is now defined.
If I comment out the   $var_one =   I see 
Use of uninitialized value in substitution iterator at anon02.pl line 12, <DATA> line 1.
The variable is .
Any chance the variable name is misspelled in the text file?   When I tried the following data: 
__DATA__
The variable is $var_one.
The variable is $var_one2.
The variable is $Var_one.
I got error messages: 
The variable is now defined.
Use of uninitialized value in substitution iterator at anon02.pl line 14, <DATA> line 2.
The variable is .
Use of uninitialized value in substitution iterator at anon02.pl line 14, <DATA> line 3.
The variable is .

In reply to Re: Re: Re: about scope and s///eeg by shenme
in thread about scope and s///eeg by Anonymous Monk

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