I beg your monkness with a basic problem. I have two text files:
<file#1> 
applebananapearcarrotcarrotbeardeerdeer
goatcowduckswanchickenmouseratbirdmouse
chocolatedogdogfishmousecatdeerbird
newyorkcalifornianewjerseymousecatdeerbird

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<file#2> 
monksbicyclewindbikecars
computercomputerprinters
hellicopterairplaneshelf
chocolatedogdogfishmouse
printerprintermousecouch

.
.
goes on for another 600,000 lines

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The output should be:
catdeerbird
Which is the 3rd line in <File#1> and the 4th line of <File#2>.
I anticipate that there will be several thousand lines that will partially match. For any line which both files share the first 24 characters (they match) and thus I want to output after the 24 characters for those particular lines of <File#1>.

I did supersearch, talked on CB and asked if I could temporarily mask for <File#1> after the 24th character and once it then matches with a line inside <File#2> it would print out those masked characters. Anno said I should implement substr. I have put together a basic version but obviously I really need help with this. 
#!/usr/bin/perl -w
use strict;
my %lines;
my %lines2;
my $str2;
open(UNIQUES,"<$ARGV[0]");
open(ALL, "<$ARGV[1]");

while (<UNIQUES>)
    {
    $lines{$str1} = 1;
    }

while (<ALL>)
    {
    print $str1 if substr( $str1, 0, 24) eq ($str2); 
    next ($str2);
    }

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Thank you for your kind assistance. Perl Monks Rule!

In reply to Compare Partial Lines of 2 Text Files by Knoperl

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