The rot13-filter.pl script calls methods on implicitly defined filehandles (STDOUT, and the result of an open() call). Prior to perl 5.13, these methods are not automatically loaded, and perl will complain with: Can't locate object method "flush" via package "IO::Handle" Let's explicitly load IO::File (which inherits from IO::Handle). That's more than we need for just "flush", but matches what perl has done since: http://perl5.git.perl.org/perl.git/commit/15e6cdd91beb4cefae4b65e855d68cf64766965d Signed-off-by: Jeff King <peff@xxxxxxxx> --- I see J6t solved this a week ago using "FileHandle". These days that is basically a compatibility synonym for IO::File. I think both should be available pretty much everywhere, so I went with IO::File for the reasons above. But if that doesn't work for some reason, switching to "use FileHandle" should be OK, too. I don't have an old enough perl easily available to test it either way. t/t0021/rot13-filter.pl | 1 + 1 file changed, 1 insertion(+) diff --git a/t/t0021/rot13-filter.pl b/t/t0021/rot13-filter.pl index e3ea58e1e..4d5697ee5 100644 --- a/t/t0021/rot13-filter.pl +++ b/t/t0021/rot13-filter.pl @@ -21,6 +21,7 @@ use strict; use warnings; +use IO::File; my $MAX_PACKET_CONTENT_SIZE = 65516; my @capabilities = @ARGV; -- 2.11.0.rc0.258.gf434c15