+sub executable_on_path ($) {
+ my ($program) = @_;
+ return 1 if $program =~ m{/};
+ my @path = split /:/, ($ENV{PATH} // "/usr/local/bin:/bin:/usr/bin");
+ foreach my $pe (@path) {
+ my $here = "$pe/$program";
+ return $here if stat_exists $here && -x _;
+ }
+ return undef;
+}
+