compatibily issue with CentOS release 6.8 (Final)

show_fingerprints.pl

@@ -42,8 +42,11 @@ foreach my $file (@files)
 
 sub get_ssh_version
 {
-  my @cmd= qw(ssh-keygen --version); # apparently, there is way to display the version directly
+  # my @cmd= qw(ssh-keygen --version); # apparently, there is way to display the version directly
+  my @cmd= qw(ssh-keygen -?); # apparently, --version does not fail as expected on some systems, e.g. openssh-5.3p1-118.1.el6_8.x86_64
+  # print "cmd: ", join (' ', @cmd), "\n";
   my $res= `@cmd 2>&1`;
+  # print "res=[$res]\n";
 
   my $version= 'unknown';
   my $has_E= 0;
@@ -58,6 +61,16 @@ sub get_ssh_version
   ($version, $has_E);
 }
 
+=head1 COMPATIBILITY
+
+=head2 Ubuntu
+
+* openssh-client 1:7.2p2-4ubuntu2.1
+
+=head2 CentOS
+
+* openssh-5.3p1-118.1.el6_8.x86_64
+
 =head1 TODO
 
 optionally display fingerprints using other hashing algorithms