open(my $master_fh => "master.file") or die "ack: $!";
open(my $subset_fh => "subset.file") or die "ack: $!";

my %subset = map { chomp; split ':', $_, 2 } <$subset_fh>;

open(my $result_fh => ">", "result.file") or die "ack: $!";

while(<$master_fh>) {
  my($key, $rest) = split ':', $_, 2;
  print {$result_fh} join ':', $key, $subset{$key}, $rest
    if exists $subset{$key};
}
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use strict;
use warnings;
open MASTER, "file1" or die "cant't open master file: $!\n";
open SUBSET, "file2" or die "can't open subset file: $!\n";
open OUT, ">outfile" or die "can't open output file: $!\n";
while ( my $sline = <SUBSET> ) {
    chomp $sline;
    my ( $subkey, $subvals ) = split /:/, $sline, 2;
    my ( $mkey, $mvals );
    while ( my $mline = <MASTER> ) {
        chomp $mline;
        ( $mkey, $mvals ) = split /:/, $mline, 2;
        last if $mkey eq $subkey;
    }
    print OUT join( ":", $subkey, $subvals, $mvals ), "\n";
}
close SUBSET;
close MASTER;
close OUT or die "couldn't close outfile: $!\n";
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The above snippet makes the assumption that the master file and the subset file are in the same order, and that every key in subset has an equal key in the master set (which is pretty much what you said). If the master file and the subset file are not in the same order, this method would need to be reworked, since synchronization is critical for its success.

this gives me an error David like it does not understand what is trying to be opened? Below is the error:

./23file.pm: open: not found
./23file.pm: open: not found
./23file.pm: open: not found
./23file.pm: syntax error at line 4: `)' unexpected
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any clues? Thanks.

Here is the code I am using

open MASTER, "file3" or die "cant't open master file: $!\n";
open SUBSET, "file2" or die "can't open subset file: $!\n";
open OUT, ">outfile" or die "can't open output file: $!\n";
while ( my $sline = <SUBSET> ) {
    chomp $sline;
    my ( $subkey, $subvals ) = split /:/, $sline, 2;
    my ( $mkey, $mvals );
    while ( my $mline = <MASTER> ) {
        chomp $mline;
        ( $mkey, $mvals ) = split /:/, $mline, 2;
        last if $mkey eq $subkey;
    }
    print OUT join ":", $subkey, $subvals, $mvals;
}
close SUBSET;
close MASTER;
close OUT or die "couldn't close outfile: $!\n";
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Sounds like you're executing the script as though it were a shell script rather than as a Perl script. Did you add a shebang line?

Also, see my minor update to the "print" line.



Dave

"If I had my life to live over again, I'd be a plumber." -- Albert Einstein

Yet another way:

$ cat master        
key1 other 1 stuff
key2 other 2 stuff
key3 other 3 stuff

$ cat subset 
key1 more 1 stuff
key3 more 3 stuff

$ cat ex.pl 
#!/usr/bin/perl -w
use strict;
my %hash;
while(<>){
    chomp;
    my($key, $rest) = split " ",$_,2;
    $hash{$key} = $rest and next if 1 .. eof;
    $hash{$key} .= " $rest" if exists $hash{$key};
}
for (sort keys %hash){
    print "$_ $hash{$_}\n";
}
__END__

$ perl ex.pl subset master 
key1 more 1 stuff other 1 stuff
key3 more 3 stuff other 3 stuff
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join -t: master other > newmaster
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Type "man join" at your unix shell prompt.:-)

Also, I interpretted

i need all of the files from the subset matched up with the same keys in the master file and the rest of the master listing concatenated onto the end of the subset keys listing

join -a1 -t: master other > newmaster
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Hope this helps!

Just tossing some pseudo code out there:

use strict ;
use warnings ;

my(%h, %h2, $f, $master, $newmaster, %db) ;
while( <$f> ) {
   @h{@KEYS} = split ;
   $db{$h{KEYFIELD} = { %h } ;

}

while( <$master> ) {
   @h2{@KEYS} = split ;
   @h2{@OTHERKEYS} = @$db{$h2{KEYFIELD}}{@OTHERKEYS} if exists $db{$h2
+{KEYFIELD}} ;
   print $newmaster join ":", @h2{@ALLKEYS} ;
}
# move new master ontop of oldmaster
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