Shell Script Frequency Calculator
A Demo Program That Calls "dc" To Do Math Calculations
Calculates Harmonics, Sub-harmonics, and Wavelength from Frequency.
=========== START ===========
#!/bin/sh
# simple text based menu system demonstration
# Arv K7HKL
# Dec. 30, 2007
#
# NOTE: This program calls the "desk calculator" (dc),
# so you need it installed to run this script.
#
frequency=7.150
while true
do
clear
echo "#==========================================#"
echo "# SIMPLE TEXT BASED MENU SYSTEM #"
echo "#------------------------------------------#"
echo "# 1) Frequency = $frequency MHz"
echo "# 2) Calculate Harmonics"
echo "# 3) Calculate Sub-Harmonics"
echo "# 4) Calculate Wavelength"
echo "# 5) "
echo "# 0) Exit #"
echo "#------------------------------------------#"
echo -n "# SELECTION: "; read selection
case $selection in
0|q|Q) exit #exit on "0", "q", or "Q".
;;
1) clear
echo
echo -n "Enter Frequency in MHz: "
read frequency
;;
2) clear
for xxx in 1 2 3 4 5 6 7 8 9 10
do
harmonic=`echo "6 k $frequency $xxx * p" | dc` # "6 K" sets the precision for dc
echo "$frequency X $xxx = $harmonic MHz"
done
echo
echo -n "Hit ENTER To Continue: "
read junk
;;
3) clear
for xxx in 1 2 3 4 5 6 7 8 9 10
do
harmonic=`echo "6 k $frequency $xxx / p" | dc` # "6 k" sets the precision for dc
echo "$Frequendy / $xxx = $harmonic"
done
echo -n "Hit ENTER To Continue: "
read junk
;;
4) clear
wavelength=`echo "6 k 492 $frequency / p" | dc` # "6 k" sets the precision for dc
echo "Wavelength for $frequency MHz = $wavelength Feet."
echo
echo -n "Hit ENTER To Continue: "
read junk
;;
5) clear
echo "Not Sure What To do With $selection Entry."
echo -n "Hit ENTER To Contunue: "
read junk
;;
*) # CatchAll for unrecognized Commands:
clear
echo
echo " Illegal Command in $selection."
echo -n "Hit ENTER To Continue: "
read junk
;;
esac # end case evaluation section
done
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