Launches Firefox in Headless mode, as background process and waits for output from Firefox. Also saves the PID of the launched Firefox to a variable.

backgroundProcessParsing.bash

#!/bin/bash

killall "firefox";

exec 3< <(firefox --headless 2>&1 & echo $!) # & firefox_pid=$!
#echo $firefox_pid &!
for i in 1 2 3 4 5; do read <&3 line; 

if [ $i -eq 1 ]; then firefox_pid="$line"
fi

if [ "$line" == "*** You are running in headless mode." ]; then echo "here is the line" 
fi


echo "$i $line"; 


done


#tempo=`$(firefox --headless) & `;
#wait
#echo "here &(<$tempo) here"


#firefox_pid=$!

# firefox --headless & 
#firefox_pid=$!


# echo $firefox_pid
# for i in 1 2 3; do read <&3 line; echo "$line"; done
#wait

# kill "$firefox_pid"

#echo $output


#kill "$firefox_pid"