use strict;
use warnings;
use Data::Dumper qw{Dumper};

my %hash = (
        'GREETING1'    => 'HAI',
        'GREETING2'  => 'HELLO',
);

              
my $value = '-GREETING1- James -POSITION- -GREETING2- -FOO-';

## find potential matches
my @matches = $value =~ m/-([^\-\s]+)-/g;

## give summary
print "" . (scalar@matches) . " matches for >>$value<<:\n" . (Dumper \@matches);

## check each potential match before substituting
for my $match (@matches){
	if (exists$hash{$match}){ # recognised?
		## make substitution, including updates on string
		print "\t>$match< replaced:\n";
		print "\tWAS : $value\n";
		$value =~s/-$match-/$hash{$match}/;
		print "\tNOW : $value\n";
	}
	else { print "$match not replaced.\n"; }
}



##</code><code>##

4 matches for >>-GREETING1- James -POSITION- -GREETING2- -FOO-<<:
$VAR1 = [
          'GREETING1',
          'POSITION',
          'GREETING2',
          'FOO'
        ];
	>GREETING1< replaced:
	WAS : -GREETING1- James -POSITION- -GREETING2- -FOO-
	NOW : HAI James -POSITION- -GREETING2- -FOO-
POSITION not replaced.
	>GREETING2< replaced:
	WAS : HAI James -POSITION- -GREETING2- -FOO-
	NOW : HAI James -POSITION- HELLO -FOO-
FOO not replaced.