I\'m trying to set a variable that should be accessible from outside PHP. Ideally this should be a local variable, but environment variables are also welcome.
First,
If you're trying to pass some output to a shell variable, you can do it like this:
$ testvar=$(php -r 'print "hello"')
$ echo $testvar
hello
Showing how export affects things:
$ php -r '$a=getenv("testvar"); print $a;'
$ export testvar
$ php -r '$a=getenv("testvar"); print $a;'
hello
In these examples, the interactive shell is the parent process and everything else shown is a child (and siblings of each other).