use strict;
use warnings;

#OPEN FILE A.txt FOR APPENDING (CHECK FOR FAILURES)
open ( FOO, ">>", 'A.txt' ) 
    or die "Could not open file A.txt: $!";

#OPEN FILE B.txt for READING (CHECK FOR FAILURES)
open ( BAR, "<", 'B.txt' ) 
    or die "Could not open file B.txt: $!";

#READ EACH LINE OF FILE B.txt (BAR) and add it to FILE A.txt (FOO)
while ( my $line = <BAR> ) {
  print FOO $line;
}
[download]

-enlil