January 26, 2010

LHS Episode #032: Screen-Doored Submarines

1 hour 26 minutes

Texas Linux Fest promo

Contributors:

Shawn Powers of Linux Journal, and a recent guest on LHS, had a house fire. If you can, please help him out.

Google alert says LHS was mentioned in the Niagara Peninsula Amateur Radio Club (NPARC) forums, but it seems to have disappeared.

There’s been a problem with Russ’ email, [email protected], so please also copy Richard, [email protected], on any email until the problem is resolved.

Michael, DL4MGM, advises WSPR users to make sure their transmitters are on frequency, so as to avoid encroaching on the visual QRSS, particularly on 30m. He also suggests using “sudo su” to get a root shell session.

Ted, WA0EIR, writes to express his appreciation for Episode 029, and the plug for his website.

Google Alert tells us that a French website, al-aide.com, reprinted the post about Episode 029.

Announcements:

Texas Linux Fest will be held in Austin, TX on April 10, 2010, at the Monarch Event Center. You might even find a Linux in the Ham Shack host there! Tracy, one of the organizers of the event, is also starting another Linux-related podcast. Keep an eye on his website for the first episode.

We’re nearing our goal of raising $750 for the LHS expedition to the Dayton Hamvention in 2010. Please click on the Donate button and make a donation, as every little bit helps. Thank you!

Links and Notes:

There has been a lot of ham radio involvement in the relief efforts in Haiti, through such groups as the Texas Baptist Men and SATERN. Russ points us to this YouTube video containing a contact with HH2JR, demonstrating the effectiveness of ham radio in emergency communications.

Richard talks about using Linux scripts to automate D-RATS transmissions (auto-QSTs). This script downloads weather information and formats it for sending through D-RATS.

#!/bin/bash

Change directory

cd /home/richard/drats/current_conditions

Remove the old downloaded weather file

rm KHQZ.TXT

Download the current weather file from NOAA

wget -q ftp://tgftp.nws.noaa.gov/data/observations/metar/decoded/KHQZ.TXT

Remove the old formatted file

rm current.txt

Strip last line of text of the NOAA file, using sed

This sed command strips out everything between “Mesquite” and “Pressure”

sed ‘/Mesquite,/,/Pressure / !d’ KHQZ.TXT > khqz1.txt

Add a blank line to the new file

echo -e " " » current.txt

Copy Mesquite Weather conditions to new file

cat khqz1.txt » current.txt

Done!

A cron job then periodically sends out the contents of current.txt

For more information on using the BASH shell and scripting, see:

Learning the BASH Shell from O’Reilly Media. (Shameless plug: You can buy the O’Reilly book through the blacksparrowmedia Amazon store)

Advanced BASH Scripting Guide

Russ discusses the Linux “screen” command.

bash (Bourne Again Shell) is one command shell program. There’s also csh, tcsh, korn, and others.

psk31lx is a PSK31 program for a terminal session.

If you have a Linux distribution with the Amateur Radio repository, such as Debian, Ubuntu, or Linux Mint, psk31lx should be available there. You can then install it with the Synaptic package manager, or with the command

apt-get install psk31lx

More about screen:

A Guide to GNU Screen

How do I Use Multiple Screens on One Terminal over ssh session?

Linux Screen Tutorial and How To

Power Sessions with Screen

GNU Screen

screen switches and command keys

Visit us on the IRC channel #lhspodcast at irc.freenode.net or call the voice message line at 888-455-0305, or +1 417 429 4069.

Music:

“Flash in a Bottle” by Dead Heart Bloom from the album “In Chains.”

“Things Happen Fast” by Fuzzy Logic.

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By Black Sparrow Media

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