Install poppler using exec() in PHP

Question

I am very new to using Linux commands. I am trying to install Poppler-Utils for Linux Using this PHP code:

exec('install poppler > /usr/local/bin/  2>&1', $output);
print_r($output);

Output:

Array ( ) 

• What does this mean?
• Is it the right way to install Poppler-Utils on a Linux Server?

Any help is appreciated!