What are you doing there?

        foreach $line (@array)
        {
        $line =~ s/\s{1}//g;
        }
[download]

You are aliasing $line to the elements of @array; but because you emptied it just before, the loop never executes at all. Even if it did, you would be substituting on the array's elements; but what you want is to do so on the line of input data.

I'll quote from perldoc -f split:

As a special case, specifying a PATTERN of space (' ') will split on white space just as split with no arguments does. Thus, split(' ') can be used to emulate awk's default behavior, whereas split(/ /) will give you as many null initial fields as there are leading spaces. A split on /\s+/ is like a split(' ') except that any leading whitespace produces a null first field.

In other words,
just @array = split (" ", $line);
and you should be fine.
(And it rhymes, too.)

I'd like to mention you should rather move the my @array; into the loop - instead of emptying the array every time over. Variables should be declared as close to where they're used as possible, and restricted to as narrow a scope as feasible.

Taking all this together and using the fact that you can perfectly well work with $_ without assigning it to something first, we get this:

#!/usr/local/bin/perl -w
use strict;

open (FH, $ARGV[0]) or die "unable to open input file: $!"; # more hel
+pful message
open (OUTFILE, ">$ARGV[1]") or die "unable to open output file: $!"; #
+ this should have one too

while (<FH>){
        chomp;
        my @array = split;

        print OUTFILE "@array\n"; # or whatever has to be done
}
[download]

As a general coding style, I would propose you don't try to handle the filenames yourself; let Perl decide about the input arguments and let the user decide, via redirection, where he wants to put the stuff. So we get this:

#!/usr/local/bin/perl -w
use strict;

while (<>){
        chomp;
        my @array = split;

        print "@array\n"; # or whatever has to be done
}
[download]

A sidenote for the curious: perl -na will build almost exactly that loop framework for you. :)

Makeshifts last the longest.