replacing some commands in an existing BASH script - bash

Question

I have the following script which sends the results of an iwlist scan via OSC:
#!/bin/bash
NUM_BANKS=20
while [[ "$input" != "\e" ]] ; do
networks=$(iwlist wlan0 scanning | awk 'BEGIN{ FS="[:=]"; OFS = " " }
/ESSID/{
#gsub(/ /,"\\ ",$2)
#gsub(/\"/,"",$2)
essid[c++]=$2
}
/Address/{
gsub(/.*Address: /,"")
address[a++]=$0
}
/Encryption key/{ encryption[d++]=$2 }
/Quality/{
gsub(/ dBm /,"")
signal[b++]=$3
}
END {
for( c in essid ) { print "/wlan_scan ",essid[c],signal[c],encryption[c] }
}'
)
read -t 0.1 input
echo "$networks" | while read network; do
set $network
hash=` echo "$2" | md5sum | awk '{ print $1 }'| tr '[:lower:]' '[:upper:]'`
bank=`echo "ibase=16;obase=A; $hash%$NUM_BANKS " | bc`
echo "$1$bank $2 $3 $4"
echo "$1$bank $2 $3 $4" | sendOSC -h localhost 9997
done
#echo "$networks" | sendOSC -h localhost 9997
done
An example of the output from this is '/wlan_scan13 BTHomehub757 -85 On', which is then sent via the sendOSC program.
I basically need to replace the iwlist scan data with the results of this tshark scan:
sudo tshark -I -i en1 -T fields -e wlan.sa_resolved -e wlan_mgt.ssid -e radiotap.dbm_antsignal type mgt subtype probe
which similarly outputs two strings and an int, outputting a result like:
'Hewlett-_91:fa:xx EE-BrightBox-mjmxxx -78'.
So eventually I want the script to give me an output in this instance of
'/wlan13 Hewlett-_91:fa:xx EE-BrightBox-mjmxxx -78'.
Both scans constantly generate results in this format at about the same rate, updating as new wifi routers are detected, and these are sent out as soon as they arrive over the sendOSC program.
This is probably a pretty simple edit for an experienced coder, but I've been trying to work this out for days and I figured I should ask for help!
If someone could clarify what needs to stay and what needs to go here I'd really appreciate it.
Many thanks.

Answer 1

Do you really want to replace commands? The sane approach would seem to be to add an option to the script to specify which piece of code to run, and include them both.
# TODO: replace with proper option parsing
case $1 in
--tshark) command=tshark_networks; shift;;
*) command=iwlist_networks;;
esac
tshark_networks () {
sudo tshark -I -i en1 -T fields \
-e wlan.sa_resolved \
-e wlan_mgt.ssid \
-e radiotap.dbm_antsignal type mgt subtype probe
}
iwlist_networks () {
iwlist wlan0 scanning | awk .... long Awk script here ....
}
while [[ "$input" != "\e" ]] ; do
networks=$($command)
read -t 0.1 input
echo "$networks" | while read network; do
: the rest as before, except fix your indentation
This also has the nice side effect that the hideous iwlist command is encapsulated in its own function, outside of the main loop.
... Well, in fact, I might refactor the main loop to
while true; do
$command |
while read a b c d; do
hash=$(echo "$b" | md5sum | awk '{ print toupper($1) }')
bank=$(echo "ibase=16;obase=A; $hash%$NUM_BANKS " | bc)
echo "$a$bank $b $c $d"
echo "$a$bank $b $c $d" | sendOSC -h localhost 9997
done
read -t 0.1 input
case $input in '\e') break;; esac
done