in reply to printing the line after grepping

use strict;
use warnings;
use autodie qw(open close);
...
open my $handle, '<', $filepath;
while (<$handle>) {
   print if /0 Items in Feed & 0 New Fetched items/;
}
close $handle;

[download]
Perl 6 - links to (nearly) everything that is Perl 6.

Replies are listed 'Best First'.
Re^2: printing the line after grepping
by 7stud (Deacon) on Nov 11, 2009 at 17:13 UTC

    A beginner's version of that would be:

    use strict;
use warnings;
use 5.010;


my $pattern = '0 Items in Feed & 0 New Fetched items';

open(my $INFILE, "<", "data2.txt") or die "There was a problem: $!";

while (my $line = <$INFILE>) {
    print $line if $line =~ /$pattern/;
}

    [download]

    If you write the while loop like this:

    while (<$INFILE>) {
    
}

    [download]

    it becomes magical in perl. Every time through the while loop, the next line from the file will be read into a variable named $_. Calling print with no arguments will print $_, and a regex will match against $_ by default.

[reply]
[d/l]
[select]
      Actually, while (my $line = <$INFILE>) is equally magical. 
      while (<$INFILE>)            => while (defined($_ = <$INFILE>)
while (my $line = <$INFILE>) => while (defined(my $line = <$INFILE>)

      [download]
[reply]
[d/l]
[select]
        Equally magical? Nothing gets assigned to $_ in the latter case.
[reply]

In Section Seekers of Perl Wisdom