perldoc open

Reveals…

System::Library::Perl:User.Contributed PeSystem::Library::Perl::5.8.8::open(3)

NAME
       open − perl pragma to set default PerlIO layers for input and output

SYNOPSIS
           use open IN  => ":crlf", OUT => ":bytes";
           use open OUT => ’:utf8’;
           use open IO  => ":encoding(iso−8859−7)";

           use open IO  => ’:locale’;

           use open ’:utf8’;
           use open ’:locale’;
           use open ’:encoding(iso−8859−7)’;

           use open ’:std’;

DESCRIPTION
       Full‐fledged support for I/O layers is now implemented provided Perl is
       configured to use PerlIO as its IO system (which is now the default).
       ...
       ...

http://fungi.yuggoth.org/weather/
http://linuxshellaccount.blogspot.com/2008/09/bash-script-to-get-weather-forecasts.html

telnet rainmaker.wunderground.com

curl http://weather.noaa.gov/pub/data/forecasts/city/state/city.txt

tcpdump -i eth0 host 192.168.1.101

Now, run the ping test:

ping 192.168.1.100

At this point, if you get an output from tcpdump, you’ll know that the packet has made its way to the target machine (192.168.1.100). The next step would be to see if you ever received an acknowledgment from the target machine. Run arp on the machine doing the pinging (192.168.1.101):

arp -an

If you see something like ? (192.168.1.112) at (incomplete) on en1 [ethernet], that means you never got an acknowledgment back from the target machine (192.168.1.100).

At this point in this scenario, we would start to dive into what could be wrong. In this particular situation, it was a driver issue with assigning a MAC address to the interface.

This is just one scenario to get you familiar with how to use tcpdump and arp and gather information about the networking issue. Please refer to the utility man pages for more information.

I think it’s easy to get the idea based on the example above, but just in case you need inspiration, you could automatically remove these empty directories with the following (Careful! This uses ‘-rf’ flag which shows no warnings or mercy!):

find /path/to/directory -type d -empty -exec rm -rf {} \;

Check out some additional methods here:

http://www.cyberciti.biz/faq/linux-unix-shell-check-if-directory-empty/

Click here to view the embedded video.

#!/bin/sh

echo "A First Method"
read -s -n 1 -p "Press any key to continue..."

# insert echo here for cleaner output
echo

echo "A Second Method"
echo "Press any key to continue..."
read -s -n 1 any_key
echo "Now exiting"
exit 0

Note: “any_key” was simply a made up name. It can be anything. As always, be sure to take a look at the man page for more information!