That seems like a contortion to avoid opening an input filehandle and a separate output filehandle. 

use strict;
use warnings;

my $filename = "inputfile.txt";
my $outputfile = $filename . "out";
my( $infh, $outfh );

open(  $infh, '<', $filename   ) or die $!;
open( $outfh, '>', $outputfile ) or die $!;

while( my $line = <$infh> ) {
    if( $line =~ /\bWilliam\b/i ) {
        print $outfh "Nick\n";
    }
    print $line;
}

close $infh  or die $!;
close $outfh or die $!;

rename $outputfile, $filename or die $!;

[download]

This is pretty close to what the -i commandline switch does for Perl one liners, with the exception of the "-i.bak" behavior, which could easily be implemented here too.

This whole thing could be written as a one liner, by the way:

perl -pi.bak -e "/\bWilliam\b/i && print qq/Nick\n/;" filename.txt

Obviously I forgot the names you're searching on, but the principle works.


Dave

In reply to Re^2: Inserting a line in the middle of a text by davido
in thread Inserting a line in the middle of a text by goude

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