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Full Discussion: Simple Question about Reading file by Perl
Top Forums Shell Programming and Scripting Simple Question about Reading file by Perl Post 302572405 by durden_tyler on Thursday 10th of November 2011 01:00:12 AM
Old 11-10-2011
Quote:
Originally Posted by Damon_Qu
...
I just write a simple function to read the file line by line.
But when I run it it says out of memory.
I am not sure about the root cause, Can someone help me out of this?

Code:
#! /usr/bin/perl

use strict;

sub checkAPs{
        my $NDPDir = "/home/eweiqqu/NCB/NDP_files/";
        my $gsnFile = $NDPDir . "gsn.cbd";
        print $gsnFile."\n";
        my @aps = ();
        open Handler, $gsnFile or die "cannot open gsn.cbd";
        my @lines =<Handler>;
        while (@lines){
                push @aps, $3;
        }
        close(Handler);
        while (@aps){
                print $_." ";
        }
}

&checkAPs;

You are **NOT** reading the file line by line. You are storing the entire file contents into an array called @lines. So if your file is huge, the program will run out of memory.

tyler_durden
 

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VCDXMINFO(1)							   User Commands						      VCDXMINFO(1)

NAME

       vcdxminfo - manual page for vcdxminfo 0.7.24

SYNOPSIS

       vcdxminfo [OPTION...]

DESCRIPTION

       -i, --generic-info
	      show generic information

       -a, --dump-aps
	      dump APS data

       --relaxed-aps
	      relax APS constraints

       -o, --output-file=FILE
	      file for XML output

       -p, --progress
	      show progress

       -v, --verbose
	      be verbose

       -q, --quiet
	      show only critical messages

       --gui  enable GUI mode

       -V, --version
	      display version and copyright information and exit

   Help options:
       -?, --help
	      Show this help message

       --usage
	      Display brief usage message

AUTHOR

       Written by Herbert Valerio Riedel and Rocky Bernstein.

       http://www.gnu.org/software/vcdimager/

COPYRIGHT

       Copyright (C) 2000-2003 Herbert Valerio Riedel <hvr@gnu.org>

	      2003 Rocky Bernstein <rocky@panix.com>

       This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
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SEE ALSO

       The full documentation for vcdxminfo is maintained as a Texinfo manual.	If the info and vcdxminfo programs are properly installed at  your
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	      info vcdxminfo

       should give you access to the complete manual.

vcdxminfo 0.7.24						    March 2011							      VCDXMINFO(1)
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