Suppressing output from exec() calls in PHP

Question

I have a number of command line scripts in PHP that use exec() to perform tasks such as restarting services, loading MySQL timezone files, etc. While exec() itself does not output anything to the screen, some of the commands I am running are forcing output that I can't seem to suppress (even with ob_start()/ob_end_clean()). For example, the following would load timezone files into MySQL. We run this periodically to make sure MySQLs timezone data is up to date:

 $command = 'mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql mysql';  exec($command, $output, $result); 

In this example, I would expect all output from the command to be written into $output, but I still get the following output forced to the screen:

Warning: Unable to load '/usr/share/zoneinfo/Asia/Riyadh87' as time zone. Skipping it. Warning: Unable to load '/usr/share/zoneinfo/Asia/Riyadh88' as time zone. Skipping it. Warning: Unable to load '/usr/share/zoneinfo/Asia/Riyadh89' as time zone. Skipping it. ... 

Is there any way to suppress this output? Redirecting to /dev/null is not ideal as that would cause PHP to continue processing without waiting for the command to complete.

Thanks in advance,
~ JamesArmes

Answer 1

Redirecting stderr alone should not influence where processing takes place, just make sure not to add an &. It should only run in the background if you redirect the output and make it run in the background.

Edit:

Cracked open cygwin, you need to redirect stderr for the first command, give this a try:

$command = 'mysql_tzinfo_to_sql /usr/share/zoneinfo 2> /dev/null | mysql mysql'; exec($command, $output, $result);