use warnings;
use strict;

my %foo = map { $_ => undef } qw( employees rates departments );

for ( keys %foo ) {
  open $foo{$_}, '>', "files/$_.txt" or die "Cannot write to $_.txt: $!\n";
}

for ( keys %foo ) {
  print { $foo{$_} } "$_\n";
}

for ( keys %foo ) {
  close ( $foo{$_} ) or die "Cannot close $_.txt: $!\n";
}

for ( keys %foo ) {
  print { $foo{$_} } "$_\n";
}