This code won't work and I don't know why
A line in the file that the hash is made from looks like this:
af361872 A1
With af361872 being the key and A1 being the value
I'm trying to add the value to the second file in which each line looks like this:
0_0 af457052
The console says this
Use of uninitialized value in concatenation (.) or string at final.pl line 29, <FILE>
line 29 is "print OUT "$_\t$hash{$word-1}\n";"

use warnings;
use strict;
my %hash;
    
        open FILES,"Final.txt"or  die "Can not open file";
        
        while(<FILES>){
            chomp $_; 
            my @words; 
            @words=split(/\t/,$_); 
            
            my $len=scalar(@words)-1;
            
         $hash{$words[$len]}=$words[0];
         
}
    open FILE,"output.txt" or  die "Can not open file";<br>
    open OUT, ">cladeST.txt" or  die "Can not open file Final.txt"; 
                
        
        while(<FILE>){<br>
            chomp $_;
              
            my @word;
            @word=split(/\t/,$_);
            print OUT "$_\t$hash{$word[-1]}\n";
}
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