get average of times that take job finish in for loop shell script - linux

Question

Here is my first shell script
#!/bin/bash
COUNTER=0
while [ $COUNTER -lt 10000 ]; do
date;
time wget -q 'http://exmple.com/' > /dev/null | grep real;
sleep 3;
let COUNTER=COUNTER+1
done
echo ${COUNTER} Request Sent\n
Average Response Time is :
this script download page content and calculate time of page response
i need to store Real parameter and calculate average of it
the output of script is something like that
Tue Oct 25 22:43:36
real 0m13.275s
user 0m0.004s
sys 0m0.008s
So my problems are :
How can i add some jobs (like echo ${COUNTER} ) after pressing crtl+c (stopping script)
How can i store value of "real" in seconds // sometimes page response goes to minutes , so basically need some time convert function (?)
i tried to solve the problems but as i mentioned i am training shell script

Answer 1

#!/bin/bash
echo "How many runs would you like to perform?"
read limit
total_time=0
counter=1
while [ ${counter} -le ${limit} ]
do
date
run_time=`(time -p wget -qO- http://exmple.com/) 2>&1 > /dev/null | grep real | awk '{print $2}'`
echo "Run ${counter} completed in ${run_time} seconds"
total_time=$(bc<<<"${total_time}+${run_time}")
if [ ${counter} -ne ${limit} ]
then
sleep 3
let counter=counter+1
fi
done
avg=$(printf "%.3f" "$(bc -l <<<"${total_time}/${limit}")")
echo "${counter} requests were sent taking ${total_time} seconds"
echo "Average response time was : ${avg} seconds"
Above is a modified script to perform the operations you requested, with a couple modifications
Added a question then input to ask how many runs to make each time, instead of a static number
Print out total time for runs and then average per run in 3 decimal places
Skip sleeping if it's the last run
You'll notice we use bc instead of let for a couple math lines. The bc command allows the use of decimal places.
https://www.gnu.org/software/bc/manual/html_mono/bc.html
To get the value in seconds I had to use awk to separate the value from the title 'real' in the line. Then you can do the math on the number value.
One other thing I noticed in your initial script. You used both ways of displaying a variable:
$COUNTER and ${COUNTER}
While both are legitimate, I got into the habit of always encapsulating my variables, it makes things easier when you want to add to the end of it.
For example let's say I have a number defined (NUM=7), but want to display it times 10. If I don't encapsulate echo $NUM0 then I get an error because the variable $NUM0 wasn't defined. But if I encapsulate echo ${NUM}0 will display an output of 70.
All of this results in a final output as below
How many runs would you like to perform?
5
Tue Oct 25 16:02:58 MST 2016
Run 1 completed in 0.09 seconds
Tue Oct 25 16:03:01 MST 2016
Run 2 completed in 0.08 seconds
Tue Oct 25 16:03:05 MST 2016
Run 3 completed in 0.07 seconds
Tue Oct 25 16:03:08 MST 2016
Run 4 completed in 0.09 seconds
Tue Oct 25 16:03:11 MST 2016
Run 5 completed in 0.08 seconds
5 requests sent taking .41 seconds
Average response time was : 0.08 seconds
Please let me know if you have any other questions about the script.

Answer 2

You can record a reasonably precise time with e.g.
t1=$(date +%s.%N)
wget ...
t2=$(date +%s.%N)
diff=$(($t2-$t1))
For doing stuff after Ctrl+C, which is really a SIGINT signal, read up about the trap builtin.