BEGIN {
  unless ($ENV{PATH} =~ m#/foo/bin#) {
    $ENV{PATH} = "/foo/bin:/bar/bin:$ENV{PATH}";
    $ENV{LD_LIBRARY_PATH} = "/foo/bin:/bar/bin:$ENV{LD_LIBRARY_PATH}";
    $ENV{PERL5LIB} = "/foo/lib:$ENV{PERL5LIB}";
    exec("$0 @ARGV");
    exit;
  }
}
use foo;