You are right about having to protect the values in @tmpl. Once you change the word DOMAIN to the first @subs value, in your original code you have changed your template itself and can no longer substitute for DOMAIN -- in your case you now need to substitute for "itchy.foo"

Try this sample code, where I substituted for the $j variable name something a bit more descriptive, and before each potential replacement saved each template string to a new "str_for_subbing" (and made up an "input" for the template file so I could see some real output).

#!/usr/bin/perl

use strict;

my @subs = qw(itchy.foo scratchy.bar homer.bab);

my @tmpl = ("To: webmaster\@DOMAIN",  "Dear Sir or Madam:", "You have 
+won \$1,000,000!");

my ($sub, $str, $str_for_subbing);

for $sub(@subs) {
  open(FH,">virt.$sub") or die;
  
  # Assume @templ in your code should have been @tmpl 
  # -- good reason to use strict!
  
  foreach $str (@tmpl) {
    $str_for_subbing = $str;
    $str_for_subbing =~ s/DOMAIN/$sub/g;
    print "$str_for_subbing\n";
    print FH "$str_for_subbing\n";
  }
  close(FH)
}

[download]

If you don't assign each $str to a $str_for_subbing, you do change the value of $str in the template on the first substitution for DOMAIN, which was not your intent. Substituting in a "copy" of each string saves you this grief.

Live in the moment.

In reply to Re: processing a file once within a nest for loop by Speedy
in thread processing a file once within a nest for loop by c

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.