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Full Discussion: perl grep implementation
Top Forums Shell Programming and Scripting perl grep implementation Post 302526584 by pludi on Wednesday 1st of June 2011 01:45:06 AM
Old 06-01-2011
First, just passing a filename as a parameter doesn't automatically open it for reading. You'll have to open it yourself. And you have to enclose any string in quotes (for Perl, ./loghttpd-05212011 is very different from "./loghttpd-05212011").

As for optimizing: don't read line-by-line, define the search regex as strict as possible (can "ERROR" occur anywhere in the line? Or at a specific position? Is there any fixed, or well defined, text leading up to it?), and if possible use the built-in grep function.

A simple example:
Code:
#!/usr/bin/perl -w

use strict;
use warnings;

sub printFun {
    my ($file) = @_;
    open my $INPUT, '<', $file or die "Can't open $file for reading: $!\n";
    print grep { /ERROR/ } <$INPUT>;
    close $INPUT;
}

printFun "./loghttpd-05212011";

 

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URI::URL(3pm)						User Contributed Perl Documentation					     URI::URL(3pm)

NAME
URI::URL - Uniform Resource Locators SYNOPSIS
$u1 = URI::URL->new($str, $base); $u2 = $u1->abs; DESCRIPTION
This module is provided for backwards compatibility with modules that depend on the interface provided by the "URI::URL" class that used to be distributed with the libwww-perl library. The following differences exist compared to the "URI" class interface: o The URI::URL module exports the url() function as an alternate constructor interface. o The constructor takes an optional $base argument. The "URI::URL" class is a subclass of "URI::WithBase". o The URI::URL->newlocal class method is the same as URI::file->new_abs. o URI::URL::strict(1) o $url->print_on method o $url->crack method o $url->full_path: same as ($uri->abs_path || "/") o $url->netloc: same as $uri->authority o $url->epath, $url->equery: same as $uri->path, $uri->query o $url->path and $url->query pass unescaped strings. o $url->path_components: same as $uri->path_segments (if you don't consider path segment parameters) o $url->params and $url->eparams methods o $url->base method. See URI::WithBase. o $url->abs and $url->rel have an optional $base argument. See URI::WithBase. o $url->frag: same as $uri->fragment o $url->keywords: same as $uri->query_keywords o $url->localpath and friends map to $uri->file. o $url->address and $url->encoded822addr: same as $uri->to for mailto URI o $url->groupart method for news URI o $url->article: same as $uri->message SEE ALSO
URI, URI::WithBase COPYRIGHT
Copyright 1998-2000 Gisle Aas. perl v5.14.2 2012-02-11 URI::URL(3pm)
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