Wedge-tailed eagles winning war of the skies against drones

Unmanned aerial vehciles become unlikely prey for wedge-tailed eagles in Western Australia’s Goldfields.

Source: Wedge-tailed eagles winning war of the skies against drones

“People couldn’t believe I was able to get such a good photo of an eagle airborne, but I didn’t … another eagle took that photo,” he said.

“I was flying the tailings dam out at St Ives and I was getting attacked by two eagles simultaneously.

Help, I’m Trapped in Facebook’s Absurd Pseudonym Purgatory

omeone reported my account as pseudonymous, and Facebook kicked me out. To get back in, I must provide various forms of identification proving the authenticity of my username. I’m not going to.

I am one of many casualties of Facebook’s recently rejiggered “authentic name” policy, wherein anonymous users can report a name as fake and trigger a verification process.

Source: Help, I’m Trapped in Facebook’s Absurd Pseudonym Purgatory | WIRED

You get what you pay for.

Sendmail Problems

You can use the mailq command sendmail -bp command to display a summary of the mail messages queued for future delivery. Type the following command:
# mailq

via Sendmail: Clear / Delete / Flush Mail Queue.

A service in a local server started to send email through my main server back to the originating server causing many errors in /var/log/maillog of my main server.  Each attempt added a message to its message queue that was blocked due to a problem with sendmail on the originating server.  The email being sent was sent automatically by a VOIP service I was testing on that originating server (not good).

You can cd to /var/spool/mqueue and delete all files if you want to get rid of all messages in the queue:
# cd /var/spool/mqueue/
# ls
# rm *

The above sequence cleared the queue so sendmail stopped trying to send those messages to a broken server at the destination.

Sendmail Problem on Originating Server

Sendmail wouldn’t start.  OS Fedora 19 so it’s running that new systemd for service startup.   Here are pertinent error messages in  /var/log/messages:

Nov 17 21:23:39 ana systemd[1]: Starting Sendmail Mail Transport Agent...
Nov 17 21:23:39 ana sendmail[1555]: -bd is not supported by sSMTP
Nov 17 21:23:39 ana systemd[1]: PID file /run/ not readable (yet?) after start.
Nov 17 21:23:39 ana systemd[1]: Failed to start Sendmail Mail Transport Agent.
Nov 17 21:23:39 ana systemd[1]: Dependency failed for Sendmail Mail Transport Client.
Nov 17 21:23:39 ana systemd[1]: Unit sendmail.service entered failed state.

I did a lot of googling to find someone in a similar situation to no avail.  I then looked into sSMTP and why that was being called  instead of good old sendmail.  After

#yum erase sSMTP

thus purging that service entirely from the system,  sendmail starts in this Fedora 19 VM and works (knock on wood).

Calculating distance between longitude and latitude pairs

Problem: I need a simple way to calculate distance between two pairs of longitude and latitude coordinates.

Apparently there are several ways of making this calculation.  Since none of my calculations would exceed 15 miles I was able to use the flat earth calculation which is the simplest but inaccurate as distances increase between the two points according to this wikipedia article.  Here’s a blurb about the flat-earth formula:

Flat-surface formula

A planar approximation for the surface of the earth may be useful over small distances. The accuracy of distance calculations using this approximation become increasingly inaccurate as:

  • The separation between the points becomes greater;
  • A point becomes closer to a geographic pole.

There were a bunch of sites that came up with all the different formulae over this but I’m not launching a satellite or programming a guided missile. The following code came from perlmonks which is a very reputable reference for anything to do with programming in perl. Here is the subroutine I chose to use. Article was written in 2002.

use Math::Trig
sub FlatEarth {
my ($lat1, $long1, $lat2, $long2) = @_;
my $r=3956; my $a = (pi/2)- deg2rad($lat1);
my $b = (pi/2)- deg2rad($lat2)
my $c = sqrt($a**2 + $b**2 - 2 * $a *$b *cos(deg2rad($long2)-deg2rad($long1)));
my $dist = $c * $r; return $dist;

Via Finding the Distance between longitude and latitude pairs.

The above code seems to work.  Most of the calculations I needed to do were under a mile.

Anyone else experiencing high rates of Linux server crashes during a leap second day?


Ok people, here’s how I worked around it.

  1. disabled ntp: /etc/init.d/ntp stop
  2. created (code stolen from Marco, see blog posts in comments)
  3. ran without an argument to see that there was a leap second set
  4. ran with an argument to remove the leap second

via debian – Anyone else experiencing high rates of Linux server crashes during a leap second day? – Server Fault.

TCPDUMP question

It seems to work as expected for me, but I did notice one thing. When I first tried to run the program as root, it failed to create the first file with a permission error. It turns out that tcpdump changes uid/gid internally to the user/group tcpdump. Since that user/group did not have write access to the directory, it failed. Once I created a subdir and gave tcpdump ownership of the subdir (chown/chgrp), tcpdump performed as expected.

via TCPDUMP question –

“mount.nfs4: Operation not permitted” when mounting NFS device

This is a configuration issue. A required parameter needs to be added to the file /etc/exports to define the root file system for mounting.

The parameter that needs to be added follows:


An example line would look like the following:

/storage *(rw,fsid=0,sync,insecure_locks,insecure,no_root_squash)

Additional information

NFSv4 works differently and no longer references the root of the file system but instead requires the root to be defined with fsid=0.

If fsid=0 is not present, permission will never be granted for the file system to be mounted.

via RHEL6: “mount.nfs4: Operation not permitted” when mounting NFS device – IBM System Cluster 1350 (1410).

NFS4 is different.   After configuring exportfs the old fashioned way the nfs mounts did not work at all.  I narrowed it down to the CentOS server running nfs4 and then found this article from IBM.  It seems to work now.

CentOS 64 bit bad ELF interpreter

You’re on a 64-bit system, and don’t have 32-bit library support installed.

sudo yum install glibc.i686

via linux – CentOS 64 bit bad ELF interpreter – Stack Overflow.

Also had to yum install gtk2.i686.  Here’s the solution from the above link for  Debian based systems:

Updated: Since it seems this answer is still getting viewed, and occassionally up-voted, note that the solution above works on CentOS, Fedora, or Red Hat derived operating systems; on a Debian or Ubuntu derived system, however, one would instead use

 sudo apt-get install ia32-lib 

For some reason, after all these years of using 64 bit OSs, and still having an active, running FC10 installation, this was the first time I had no choice but to run a 32-bit app on a 64 bit machine.
The above solution worked