php shell_exec is not showing result

Question

im trying to check bandwidth of my server from php file

so in linux i use this command

iftop -t -s 1 -n -N 2>/dev/null | awk '/Total send rate:/ {print $6}'

this id command from which i get output example: 149Mb

so i try to print that in php but is not working im using

$output = shell_exec("iftop -t -s 1 -n -N 2>/dev/null | awk '/Total send rate:/ {print $6}'");
echo "$output";

so i dont get output (example 149Mb) when i visit mypage.php

Answer 1

Could it be because of $6 getting interpolated? What is the output you are getting? Try this:

$output = shell_exec("iftop -t -s 1 -n -N 2>/dev/null | awk '/Total send rate:/ {print \$6}'");