[Courses] [Perl] Part 6: Data Extraction with m//

[Karine Delvare]

On Fri, 06 May 2005 16:11:00 +0100
Dan <dan at cellectivity.com> wrote:

> LinuxChix Perl Course Part 6: Data Extraction with m//
> 
> 4) Exercise
> 
> Modify your program from last week's exercise, the one that reads
> /etc/passwd, so that it outputs only your home directory and your
> shell (not the rest of the line).

#!/usr/bin/perl -w
use strict;

open MY_INPUT, "< /etc/passwd" or die "Couldn't open input file: $!";

print "Please enter a username:\n";
chomp(my $user = <STDIN>);

my $found = 0;
my $home;
my $shell;

while (defined(my $line = <MY_INPUT>))
{
	if (($home, $shell) = ($line =~ /^$user:.*:(.*):(.*)$/))
	{
		print "Home is: $home\nShell is: $shell\n";
		$found = 1;
	}
}

if (!$found)
{
	print "This user does not exist.\n";
}

close MY_INPUT;



Provided I'm sure shell is the last info and home the one before that, I decided to use a greedy match for all the info between the user and the home directory.
Does greedy / non-greedy affect performances?

-- 
Karine Delvare
http://edhel.nerim.net/