use strict;
use warnings;

local %ENV = %ENV; # NOTE: local is used here in case you wish to 
                   # restore the original %ENV in a different scope
                   # of this script
$ENV{CTC_HOME} = q{/Inf/work/};
# ... now "CTC_HOME" is available for all child
# processes (via fork, system, ``, etc) of $0 (this script)