shell_exec returns empty string

php shell-exec
Risto Novik picture Risto Novik · Jun 24, 2011 · Viewed 12.2k times · Source

When I execute my command in PHP with shell_exec it always returns an empty string. I tried shell_exec('ls -l'); and it works. I put the command as a separate file and still same result.

$shellOutput = shell_exec("pacmd list-sinks | grep 'volume: 0:' | tail -1 | awk '{ print $3 }'");

//return execute status;
echo trim($shellOutput);

Answer

cyrusv picture cyrusv · Nov 30, 2011

I changed the sudoers to ALL ALL = (ALL) :NOPASSWD ALL (very un-secure, but just to find something sure to work),

then I did a

sudo -u myusername /path/to/script.sh

where script.sh has export VAR=value export VAR=value

for all the environmental variables that are necessary (you can do a printenv from a user who can properly pacmd to see what you need. probably a good HOME and maybe an XAUTHORITY).

hope that helps

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