ddrew78 has asked for the wisdom of the Perl Monks concerning the following question:

I have a file that looks something like this: 
 ip vrf forwarding ABC:Defgh
 ip address 1.1.1.1 255.255.255.252
 ip vrf forwarding ABD: Efghi
 ip address 2.2.2.2 255.255.255.252

[download]
what I'm trying to do is find each line that begins with 'ip address' and copy it directly below, so it looks like this: 
 ip vrf forwarding ABC:Defgh
 ip address 1.1.1.1 255.255.255.252
 ip address 1.1.1.1 255.255.255.252
 ip vrf forwarding ABD: Efghi
 ip address 2.2.2.2 255.255.255.252
 ip address 2.2.2.2 255.255.255.252

[download]
I've been searching the web over, but all everybody wants to do is get rid of duplicates. Any ideas? And no, this is not homework, this is a script I'm trying to write to run in our network...I hav the rest of it done, but can't seem to be able to duplicate those lines. Any help is greatly appreciated.

Replies are listed 'Best First'.
Re: How to duplicate lines
by jwkrahn (Abbot) on Mar 03, 2010 at 22:17 UTC 
    $ echo "ip vrf forwarding ABC:Defgh
ip address 1.1.1.1 255.255.255.252
ip vrf forwarding ABD: Efghi
ip address 2.2.2.2 255.255.255.252" | perl -pe'$_ .= $_ if /^ip addres
+s/'
ip vrf forwarding ABC:Defgh
ip address 1.1.1.1 255.255.255.252
ip address 1.1.1.1 255.255.255.252
ip vrf forwarding ABD: Efghi
ip address 2.2.2.2 255.255.255.252
ip address 2.2.2.2 255.255.255.252

    [download]
[reply]
[d/l]
      Thanks to everyone for the quick responses. However, I made a crucial mistake when I showed what it needs to become. What I actually need to change it to needs to be 
       ip vrf forwarding ABC:Defgh
ip address 1.1.1.1 255.255.255.252
ip address 1.1.1.1 255.255.255.100
ip vrf forwarding ABD: Efghi
ip address 2.2.2.2 255.255.255.252
ip address 2.2.2.2 255.255.255.100

      [download]
      The last part of the duplicated line needs to change as it is being copied. Is there any way of doing this?
[reply]
[d/l]
        Change the code given above to:

        perl -pe'$_ .= $_, s/252$/100/  if /^ip address/'

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[d/l]
Re: How to duplicate lines
by jrsimmon (Hermit) on Mar 03, 2010 at 22:23 UTC 
    use strict;
my $pattern = 'ip address';
open IN_FILE, '<', 'some_file' or die $!;
open OUT_FILE, '>', 'some_other_file' or die $!;
while(my $line = <FILE>){
  print OUT_FILE $line;
  print OUT_FILE $line if $line =~ /^$pattern/;
}
close(IN_FILE);
close(OUT_FILE);

    [download]
[reply]
[d/l]
Re: How to duplicate lines
by BrowserUk (Patriarch) on Mar 03, 2010 at 22:32 UTC 
    perl -pe"print if /address/" in >out

    [download]
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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[d/l]
Re: How to duplicate lines
by ungalnanban (Pilgrim) on Mar 04, 2010 at 04:49 UTC
    See the following code:
    it will duplicate the lines starting with "ip address" 
    use strict;
use warnings;
open(FH,"data");
foreach(<FH>) {
   print $_;
   if ( $_ =~ m/^ip address/)   {print $_;}
}

    [download]

    --sugumar--
[reply]
[d/l]
Re: How to duplicate lines
by bichonfrise74 (Vicar) on Mar 04, 2010 at 00:06 UTC
    Something like this? 
    #!/usr/bin/perl

use strict;

while (my $line = <DATA>) {
    print $line;
    if ( $line =~ /\sip address/ ) {
        $line =~ s/(\d+.\d+.\d+.)252/${1}100/;
        print $line;
    }
}

__DATA__
 ip vrf forwarding ABC:Defgh
 ip address 1.1.1.1 255.255.255.252
 ip vrf forwarding ABD: Efghi
 ip address 2.2.2.2 255.255.255.252

    [download]
[reply]
[d/l]
      Great, thank you so much. That did the trick.
[reply]

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