It's generally good form to indicate if you've Crossposted to Stack Overflow and Unix & Linux Stack Exchange to prevent duplication of effort.
The answer I posted on Stack Overflow was:
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
#read file1 into a hash - but invert is it's value => key instead:
# 'CKEIFJ' => 'cmr03lsp',
# etc.
open( my $file1, '<', "file1.txt" ) or die $!;
my %file1_content = map { reverse split } <$file1>;
close($file1);
print Dumper \%file1_content;
#read file 2 - read keys, store the values.
#split _2_ fields, so we keep both numbers as a substring:
#e.g.:
# 'cmr03lsp' => '60 70
#',
open( my $file2, '<', "file2.txt" ) or die $!;
my %file2_content = map { split( " ", $_, 2 ) } <$file2>;
close($file2);
print Dumper \%file2_content;
#then iterate file 3, checking if:
#file1 has a matching 'key' (but inverted - as a value)
#file2 has a cross reference.
open( my $file3, '<', "file3.txt" ) or die $!;
while ( my $line = <$file3> ) {
chomp $line;
if ( $file1_content{$line}
and $file2_content{ $file1_content{$line} } )
{
print
"$file1_content{$line} $line $file2_content{$file1_con
+tent{$line}}";
}
}
close($file3);
Which prints (aside from Dumper diag content):
fji01dde AIDJFMGKG 25 30
cmr03lsp CKEIFJ 60 70
as requested
