Shell Programming and Scripting

#!/usr/bin/expect
set ip [lindex $argv 0]
spawn telnet $ip
exec > "$2"
sleep 2
for h in {0..20}
    do
    echo "Running test $h"
    send "iwconfig wlan0 | grep -o \"Signal level=....\" | cut -c14-16"

    set val $expect_out(buffer)

    echo "RSSI: $val"

    result +=val
done
result = result/20
echo "Average RSSI &result"

#!/usr/bin/expect -f
set timeout 8
#log_user 0
set ip [lindex $argv 0]
spawn -noecho telnet $ip
sleep 2
set count 0
set result 0
send "PS1='PROMPT# '\r"
expect -re "PROMPT# '(.*)PROMPT# "
while {$count < 20} {
    send "./iwconfig wanl | grep -o \"Signal level=....\" | cut -c14-16\r"
    expect -re "\r\n(.*)\r\n(.*)PROMPT# "
    set val $expect_out(1,string)
    set result [expr $result+$val ]
    set count [expr $count+1 ]
}
send "exit\r"
expect eof
set result [expr $result/20 ]
puts "Average RSSI $result"

#!/usr/bin/expect -f

set timeout 8
log_user 0
set ip [lindex $argv 0]
spawn -noecho telnet $ip
sleep 2

set count 0
set result 0
set value 0
set resultDb 0

send "PS1='PROMPT# '\r"

expect -re "PROMPT# '(.*)PROMPT# "
while {$count < 20} {
send "iwconfig wlan0 | grep -o \"Signal level=....\" | cut -c14-16\r"
expect -re "\r\n(.*)\r\n(.*)PROMPT# "
set valdB $expect_out(1,string)
set value 10^($valdB/10)
set result [expr $result+$value ]
set count [expr $count+1 ]
}
send "exit\r"
expect eof

set result [expr $result/20 ]
set resultdB 10*log(($result/10)/log(10))

puts "Average RSSI $resultdB"

$ tail -5 iw_avg.expect 
set result [expr $result/20.0 ]
set resultStr 10*log(($result/10.0)/log(10))
set resultVal [expr 10*log(($result/10.0)/log(10))]

puts "Average RSSI $resultVal ($resultStr)"

$ ./iw_avg.expect testSrv
Average RSSI 51.740556616639076 (10*log((4067.05/10.0)/log(10)))

$ bc -l
10*l((4067.05/10)/l(10))
51.74055661663907746850

set val [expr 10^($val/10)]

#!/usr/bin/expect -f

set timeout 8
log_user 0
set ip [lindex $argv 0]
spawn -noecho telnet $ip
sleep 2

set count 0
set result 0.0
set val 0.0

send "PS1='PROMPT# '\r"

expect -re "PROMPT# '(.*)PROMPT# "
while {$count < 20} {
    send "iwconfig wlan0 | grep -o \"Signal level=....\" | cut -c14-16\r"
    expect -re "\r\n(.*)\r\n(.*)PROMPT# "
    set val $expect_out(1,string)
    puts "$val"
    #convert
    set val [expr 10^($val/10)]
    puts "$val"
    set result [expr $result+$val ]
    puts "$result"
    set count [expr $count+1 ]
}
send "exit\r"
expect eof
puts "$result"
#average
set result [expr $result/20.0 ]
puts "$result"
#convert back to dB
puts "$result"
set result [expr 10*log(($result/10.0)/log(10))]

puts "Average RSSI $result"

set val [expr pow(10,$val/10.0)]