Hi madtoperl,

A number of suggestions, actually...

  1. You should use "strict" and "warnings".
  2. You should use the 3-arg form of open.
  3. You should check for failure conditions, such as open failing, or @ARGV not being set.
  4. If you use the module FileHandle, your filehandles don't have to be typeglobs.
  5. It is redundant to do ($_ =~ /.../); instead just do (/.../).
  6. If you use regex captures, you don't have to split afterwards.
  7. You're not using $changeflag; get rid of it.
  8. Finally, you're writing every line to the file, so why not just do a regex substitution and, if it fails, write the line anyway?
  9. It's considered good form (though not technically necessary in this case) to close your files when you're done with them.

Here's my rewrite: 

#!/usr/bin/perl -w

use strict;
use warnings;

use FileHandle;

(my $argact = shift) or die "Syntax:  $0  <fileid>\n";
my $input   = new FileHandle;
my $newfile = new FileHandle;

open($input,   "<", "one.txt") or die "Failed to read 'one.txt' ($!)\n
+";
open($newfile, ">", "output")  or die "Failed to write 'output' ($!)\n
+";

while(<$input>){
    s/^Authentication\s+number\s+is\s+(\d+)/Authentication number is $
+argact/;
    print $newfile "$_";
}

close $input;
close $newfile;

[download]

Isn't that a lot cleaner?

s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/

In reply to Re: File modification by liverpole
in thread File modification by madtoperl

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.