Subj : bash scripting
To   : All
From : Sean Dennis
Date : Sun Apr 06 2025 20:35:04

Hi everyone,

I thought I'd share an interesting script I wrote with some help from the 
Internet.

I am a fan of space weather and NOAA publishes a three-day space weather 
forecast that I wanted to post into the
Fidonet HAM echo and in Micronet's MIN_WEATHER echo.  Unfortunately, cron does 
not work with a three-day
schedule.  Here's what I finally came up with (the last procedure is how I 
post the message into MBSE):

===
#!/bin/bash
# The following is from:
# 
https://askubuntu.com/questions/829408/execute-bash-script-literally-after-ever
y-3-days
# This is to account for actually running every three days
# correctly since cron can't do it.

# Minimum delay between two script executions, in seconds. 
seconds=$((60*60*24*3))

# Compare the difference between this script's modification time stamp 
# and the current date with the given minimum delay in seconds. 
# Exit with error code 1 if the minimum delay is not exceeded yet.
if test "$(($(date "+%s")-$(date -r "$0" "+%s")))" -lt "$seconds" ; then
    echo "This script may not yet be started again."
    exit 1
fi

# Store the current date as modification time stamp of this script file
touch -m -- "$0"

# Insert your normal script here:
MBSE_ROOT=/opt/mbse;export MBSE_ROOT
cd $MBSE_ROOT/temp
lynx -dump "https://services.swpc.noaa.gov/text/3-day-forecast.txt" > forecast
# Micronet MIN_WEATHER
$MBSE_ROOT/bin/mbmsg post "Sean Dennis" All 65  "3 Day Space Weather Forecast" 
../forecast - -quiet
# Fidonet HAM
$MBSE_ROOT/bin/mbmsg post "Sean Dennis" All 117  "3 Day Space Weather 
Forecast" ./forecast - -quiet
cp ./forecast $MBSE_ROOT/share/int/txtfiles/en/space_forecast.asc
### Kill off the text file
rm -f ./forecast
===

-- Sean


.... Health is merely the slowest possible rate at which one can die.
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 * Origin: Outpost BBS * Johnson City, TN (86:10/1)

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