[perl] Perl read line by line

I have a simple Perl script to read a file line by line. Code is below. I want to display two lines and break the loop. But it doesn't work. Where is the bug?

$file='SnPmaster.txt';
open(INFO, $file) or die("Could not open  file.");

$count = 0; 
foreach $line (<INFO>)  {   
    print $line;    
    if ($++counter == 2){
      last;
    }
}
close(INFO);

This question is related to perl

The answer is


In bash foo is the name of the variable, and $ is an operator which means 'get the value of'.

In perl $foo is the name of the variable.


#!/usr/bin/perl
use utf8                       ;
use 5.10.1                     ;
use strict                     ;
use autodie                    ;
use warnings FATAL => q  ?all?;
binmode STDOUT     => q ?:utf8?;                  END {
close   STDOUT                 ;                     }
our    $FOLIO      =  q + SnPmaster.txt +            ;
open    FOLIO                  ;                 END {
close   FOLIO                  ;                     }
binmode FOLIO      => q{       :crlf
                               :encoding(CP-1252)    };
while (<FOLIO>)  { print       ;                     }
       continue  { ${.} ^015^  __LINE__  ||   exit   }
                                                                                                                                                                                                                                              __END__
unlink  $FOLIO                 ;
unlink ~$HOME ||
  clri ~$HOME                  ;
reboot                         ;

you need to use ++$counter, not $++counter, hence the reason it isn't working..


With these types of complex programs, it's better to let Perl generate the Perl code for you:

$ perl -MO=Deparse -pe'exit if $.>2'

Which will gladly tell you the answer,

LINE: while (defined($_ = <ARGV>)) {
    exit if $. > 2;
}
continue {
    die "-p destination: $!\n" unless print $_;
}

Alternatively, you can simply run it as such from the command line,

$ perl -pe'exit if$.>2' file.txt