In the example below, what do the deep accents in the second line mean?
$cmd = "$ffmpeg -i $video -deinterlace -an -ss $second -t 00:00:01 -r 1 -y -vcodec mjpeg -f mjpeg $image 2>&1"; $return = `$cmd`
Executes a shell command. Thus, it does everything that is in $ cmd.
See backtick statement
This is a shorthand for exec() . The output of the command can be directly used in the expression.http://php.net/manual/en/language.operators.execution.php
exec()
(Note that you should still apply escapeshellarg() to variables on the command line beforehand.)
escapeshellarg()