Example: the text file might look like this:  Hello $NAME.  How are you?

And let's say, for simplicity sake, that my perl file has a line like this:
$NAME = "Joe";

Of course, I have like 50 variables. Before I had to create "placeholders"
for the names like:

open (FILE, "filename.txt");
$printtemp = join ('',<FILE>);
close (FILE);
$printtemp =~ s#<!-- NAME -->#$NAME#sg;

But I really don't want to do that for ALL of them. Unfortunately, that's
all I know how to do.

Anybody have an easier way to open up a file and replace the exact variables
without having to create variable placeholders and substitute them one at a
time like I did in the above example?

my $foo = 'hello $bar - are you all${baz}th $boo';

my $bar = 'world';
my $baz = 'rig';
my $boo = 'tonight?';

print $_ if ($_=$foo)=~s/(.*?)(\$[\w{]+}?)(.*?)/join'',$1,eval$2,$3/eg;

undef $/; # use a block and local() in stead if you need $/ in other places
$printtemp = <FILE>;

I think you should use some kind of markup ($XXX or <%&XXX> or whatever)
and then use a substitution regex to extract the "keyword" and replace
the markup sequence with values that you keep in a hash. Dont let the
variable's names carry semanthics - it's bad design:

#!/usr/bin/perl -w

use strict;

my %symbols = (
               NAME => "Albert",
               DOG  => "Fido",
               CAR  => "Dodge"
               );

undef $/;
my $text = <DATA>; # this can be questioned by the way, but if the file's
                   # not huge it's OK

$text =~ s/%!([^!]+)!%/$symbols{ $1 }/g;

print $text;

__DATA__
Hello! My name is %!NAME!%, and all I ever do
is walking my dog %!DOG!%. That is unless
I'm out for a spin in my %!CAR!%.

Take a look at the Text::Template module.
It is doing exactly this (and much more).