How to modify a file

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

Hi everyone, I have this code that makes some changes from a file to the content of it, is there a way to modify that file so the output is printed on a new file, instead of printing the output on the screen.

Here is the code I have:

#!/usr/local/bin/perl 
open my $FILE, '<', 'rapipago.txt' or die "Cannot open file1.txt: $!";
use strict;
use warnings;
use feature 'say';
while (my $text = <$FILE>) {
    chomp $text;
    my @cums = (0);
    my @offs = ( 17, 6, 31, 3, 3 );
    my @cums = ( 0 );
    push @cums, $_ + $cums[ -1 ] for @offs;
    substr $text, $_, 0, q{-} for reverse @cums[ 1 .. $#cums ];
say $text;
}
[download]

Comment on How to modify a file Download Code

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Re: How to modify a file by Random_Walk (Prior) on Apr 25, 2013 at 13:42 UTC
Of course. Perl can do anything :) `# Add this somewhere before the loop # open output file my $outfile = "some_filename.ext"; open my $out, '>', $outfile or die "can't open $outfile: $!\n";` [download] then change `say $text;` to `say $out $text;`. Look out!, there is no comma, between the output file handle and the data you want to send to it. Cheers, R. Pereant, qui ante nos nostra dixerunt!	[reply] [d/l] [select]
Re^2: How to modify a file by static0verdrive (Initiate) on Apr 25, 2013 at 13:58 UTC
One small note... with only one '>' in the open line, the file will be overwritten each time this script runs. If you want to create a file to write to or append to it if it exists already be sure to use 2 '>>' instead. Here's how I do it: `my $logfile = "/var/log/my.log" my $text = "Log entry text!" open(LOG, ">>$logfile") or die "Could not open file: $!"; print LOG $text; close LOG;` [download]	[reply] [d/l]
Re^2: How to modify a file by biancoari (Initiate) on Apr 25, 2013 at 17:05 UTC
Hi, I made this modification: `#!/usr/local/bin/perl open my $FILE, '<', 'rapipago.txt' or die "Cannot open file1.txt: $!"; my $outfile = "rapipagomod.txt"; open my $out, '>', $outfile or die "can't open $outfile: $!\n"; use strict; use warnings; use feature 'say'; while (my $text = <$FILE>) { chomp $text; my @cums = (0); my @offs = ( 17, 6, 31, 3, 3 ); my @cums = ( 0 ); push @cums, $_ + $cums[ -1 ] for @offs; substr $text, $_, 0, q{-} for reverse @cums[ 1 .. $#cums ]; say $outfile $text; }` [download] And I am receiving this error: "Can't use string ("rapipagomod.txt")as a symbol ref while "strict refs" in use at C:\Users\ARIBIA~1\Desktop\Rapipago.pl line 15, <$FILE> line1."	[reply] [d/l]
Re^3: How to modify a file by poj (Abbot) on Apr 25, 2013 at 18:06 UTC
`$outfile` is the filename. You need to use the file handle `$out.` `say $out $text;` poj	[reply] [d/l] [select]
Re: How to modify a file by BillKSmith (Monsignor) on Apr 25, 2013 at 14:28 UTC
See the runtime flags p and perhaps i in perlrun Bill	[reply]