use strict;
use warnings;
use Data::Dump qw/pp dd/;

my $h_orig =
  {
  '/a/b/c/dt/data/SUSE/tool/0.9.0' => '/a/b/c/dt/tools/SUSE/tool/0.9.0',
  '/nfs/us' => '/usr/bin',
  '/a/b/c' => '/nfs/us'
  };


my $pattern = join "|", map quotemeta, keys %$h_orig;

my %copy = %$h_orig;

for (values %copy) {
    1 while s/^($pattern)/$h_orig->{$1}/g; 
}

pp $h_orig, \%copy;