exec() inside loop does not work?

[ignace]

This code works outside of the while, but not inside 

 

while ($row = mysql_fetch_assoc($res)) {
  $host = $row['host'];

  $cmd = exec("mysql -h$host -e \"show status like 'wsrep_cluster_size'\"");
  echo $cmd;
}

 

I have found nothing on google, stackoverflow or the php manual that explains why this does not appear to work inside a loop?

[ignace]

Phew. Found it I just needed to add escapeshellarg Can't believe I didn't try it in the first place, since it's on the PHP exec() function manual.. 

[smoseley]

What does it do inside the loop?  Does it throw an exception or just return nothing?  Likely that status variable isn't changing in the context of your loop.

[ignace]

The script appeared to hang and returned nothing. Still don't quite understand though why it works outside of the loop without the escapeshellarg() and not inside the loop. Other people have reported the same problem but they didn't have the same case as me (passed the var as second parameter) hopefully this post will help someone in the future who made the same silly mistake