use strict;
use warnings;

my $i = 1;
while (<DATA>) {
    if (s/(LKTA_mic)\d/$1$i/) {
        $i = ($i == 4) ? 1 : $i + 1;
    }
    print;
}

__DATA__
Name - John
filename "LKTA_mic4.cfg"; }
Name - Tim
filename "LKTA_mic2.cfg"; }
Name - Jane
filename "LKTA_mic1.cfg"; }
Name - Jim
filename "LKTA_mic3.cfg"; }
Name - Don
filename "LKTA_mic1.cfg"; }
Name - Cody
filename "LKTA_mic4.cfg"; }
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prints out:

Name - John
filename "LKTA_mic1.cfg"; }
Name - Tim
filename "LKTA_mic2.cfg"; }
Name - Jane
filename "LKTA_mic3.cfg"; }
Name - Jim
filename "LKTA_mic4.cfg"; }
Name - Don
filename "LKTA_mic1.cfg"; }
Name - Cody
filename "LKTA_mic2.cfg"; }
[download]

Update: changed to use capturing in regex.

Also, Search and replace

Hey, I am learning regex now, it is like head-hammering at someplaces hehe...anyways I wanted to ask you, in this line you wrote,

if(s/(LKTA_mic)\d/$1$i/)
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ok, I see that you are using backreferences to (LKTA_mic), but the way you used the variable $i, I mean, if these files were different, each one of them was a different identity in DATA, and each one of them had its unique number though the arrangement was not serial still, would they be physically re-arranged or ...according to what I could elicit here, they are merely being renamed instead? so the DATA file

Name - John
filename "LKTA_mic4.cfg"; }
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would be renamed to

Name - John
filename "LKTA_mic1.cfg"; }
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with contents intact and so on...?
##excuse my ignorance but slight not my attempts to learn##

Yes, my code does a simple text substitution, replacing a single digit (0 through 9) with the value in the $i variable.

I might be missing the point, but it sounds like you just want to read in all the names, then print them out again with a modified filename?

#!usr/bin/perl
use strict;
use warnings;
my $fpath = shift @ARGV;
open (my $fh, '<', $fpath) || die "Failed to open $fpath : $!";
my $matches = 0; ## counter for how many matches we have made
while (<$fh>){
  if ( /^(filename\s\"LKTA_mic)  ## find start of name and capture it
        \d+  ## number bit - don't capture
        (\.cfg\"\;\s\}$) ## end bit - capture
       /gx ){
    ## print out line with number modified based on how many matches w
+e have seen
    print "$1".(($matches % 4) + 1)."$2\n";
    ## increment match counter
    ++$matches;
  }
  else {
    ## didn't match so pump it straight out unmodified
    print $line;
  }
};
close $fh || die "Failed to close $fpath : $!";
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This just prints out to STDOUT, but it is easy enough to put it somewhere else!
You will find more elegant/short ways of doing this but i wanted to be clear...
Hope this helps!

Update Actually commenting the comments in the regex... and getting the filenumbers right