In my php script I generate a sequence of console commands to be executed. The sequence is strict because each next command relies on the result of the previous command. I use ';' delimiter between commands.
Under normal circumstances I just exec() that sequence and it works fine. But sometimes I need this sequence to be niced and run in background. I read that one command can be run in background by appending ' > /dev/null &' to it. But with a sequence I tried different approaches but to no avail. I feel that exec() might not be the right function for the job.
How can this be done? As far as I understand I need to prepend each command with 'nice -n 10 '.
UPDATE1:
The code I'm currently using:
$cmd[] = '...';
//...
$cmd[] = '...';
//...
if($inBackground)
{
foreach($cmd as &$command)
$command = 'nice -n 10 '.$command.' > /dev/null ';
}
if($inBackground)
exec(implode(' ; ', $cmd).' &');
else
exec(implode(' ; ', $cmd));
UPDATE2:
I changed the code using the tip from mario and now it works:
$cmd[] = '...';
//...
$cmd[] = '...';
//..
$command = implode(' ; ', $cmd);
if($inBackground)
$command = "nice sh -c '".$command."' > /dev/null &";
exec($command);
I made sure that my commands are properly escaped and don't contain single quotes.
