$lines = 0;
open(FILE, $filename) or die "Can't open `$filename': $!";
while (sysread FILE, $buffer, 4096) {
$lines += ($buffer =~ tr/\n//);
}
close FILE;

How is the above code work where it says file do i /home/vandelin/hello.pl?
or $filename gets replaced by the above? i tried both none seem to work i am just exploring and want to count the lines in hello.pl located under /home/vandelin

Learning in progress..........

$filename is a variable that holds the name of the file that you want to count its lines. There are several ways to assign that var, either hard coding or dynamically set.

# hard code the assignment
$filename = '/home/vandelin/hello.pl';
$lines = 0;
open(FILE, $filename) or die "Can't open `$filename': $!";
while (sysread FILE, $buffer, 4096) {
   $lines += ($buffer =~ tr/\n//);
}
close FILE;

you should probably start reading some Perl documentation.

Well i was reading some doccumentation and i came accross this and was like hmm i will try this and i did try i tried a couple ways so its not that i came right here i tried really..... I just thought it would be cool to do i mean im going through some tutorials and doing this and that and just came to a standstill

Learning in progress..........

you should really start from the basics
Do a

perldoc perl

on the command land. See the various topics it has. Start from perlintro

perldoc perlintro

otherwise, you can also get a Perl book that teaches you the basics.

the typical algorithm to count lines is
1) open the file
2) using a loop, go through every line, each time incrementing a counter

Something like this (Python)

num=0
for line in open("file"):
    #if its not blank lines, increment
    if not line.strip() == "": 
        num+=1
print num

Even though counting the number of lines in a file is easy to do with either Perl or Python, neither of them is the best tool for that specific task.

The best tool would be the wc command.

[root@perlman ~]# cat test
#!/usr/bin/perl
use strict;
use warnings;
use YAPE::Regex::Explain;
my $regex = qr/([-\d.]+)\s*([-\d.]+)\s*(-[\d.]+)/;
my $exp = YAPE::Regex::Explain->new($regex)->explain;
print $exp;
[root@perlman ~]# wc -l < test
10

=================

Here's a good Perl beginners book:

Learning Perl, Fourth Edition
By Randal L. Schwartz, Tom Phoenix, brian d foy
http://www.oreilly.com/catalog/lear...

well, it really doesn't matter right?
Coding in Perl/Python, saving the script as wc.py or wc.pl, and use it like wc. Serves the same purpose.

Well, I guess you entirely missed my point.

My point had nothing to do with the naming of the script. My point related to reinventing the wheel, efficiency and using the right tool for the job.

why do you think using perl/python to solve trivial things like counting lines in a file is not considered as using the 'best tool for the job' ?

Right cause if you ask me thats a pretty simple instruction. Why does it matter how you get it done ? or the tool you use to get it done? what are the benefits of using this tool compared to others ? is it easier?

Learning in progress..........