@reports = `ls *.doc`;
foreach $file(@reports) {
$cmd=`perl -ni -e 'print;print "VALUE=KEY\n" if \$\.== 3;' $file`
}

##</code><code>##

#!/usr/bin/env perl -i

use strict;
use warnings;

while (<>) {
    print;
    print "VALUE=KEY\n" if $. == 3;
    $. = 0 if eof;
}

##</code><code>##

$ ls -al *.doc
-rw-r--r--  1 ken  staff  52 26 Feb 03:20 pm_1076103_1.doc
-rw-r--r--  1 ken  staff  52 26 Feb 03:22 pm_1076103_2.doc
-rw-r--r--  1 ken  staff  52 26 Feb 03:22 pm_1076103_3.doc

$ cat pm_1076103_1.doc
Doc 1 Line 1
Doc 1 Line 2
Doc 1 Line 3
Doc 1 Line 4

$ cat pm_1076103_2.doc
Doc 2 Line 1
Doc 2 Line 2
Doc 2 Line 3
Doc 2 Line 4

$ cat pm_1076103_3.doc
Doc 3 Line 1
Doc 3 Line 2
Doc 3 Line 3
Doc 3 Line 4

##</code><code>##

$ pm_1076103.pl *.doc

##</code><code>##

$ cat pm_1076103_1.doc
Doc 1 Line 1
Doc 1 Line 2
Doc 1 Line 3
VALUE=KEY
Doc 1 Line 4

$ cat pm_1076103_2.doc
Doc 2 Line 1
Doc 2 Line 2
Doc 2 Line 3
VALUE=KEY
Doc 2 Line 4

$ cat pm_1076103_3.doc
Doc 3 Line 1
Doc 3 Line 2
Doc 3 Line 3
VALUE=KEY
Doc 3 Line 4