Question

I’d like to call system("foo") in PHP but also specify environment variables that “foo” will have access to when it runs. This is under Linux.

Any simple trick for that?

Answer 1

putenv("UNIQID=$uniqid");

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Citations from: The PHP Manual, Function Reference, putenv

For example, if a particular system command required a special value
of the environment variable LD_LIBRARY_PATH to execute successfully,
then the following code might be used on a *NIX system:

<?php
 $saved = getenv("LD_LIBRARY_PATH");        // save old value
 $newld = "/extra/library/dir:/another/path/to/lib";  // extra paths to add
 if ($saved) { $newld .= ":$saved"; }           // append old paths if any
 putenv("LD_LIBRARY_PATH=$newld");        // set new value
 system("mycommand -with args");        // do system command;
                        // mycommand is loaded using
                        // libs in the new path list
 putenv("LD_LIBRARY_PATH=$saved");        // restore old value
?>