Question itself in __ dir __ This constant points to the directory in which is that?

Answer 1, Authority 100%

This is the directory of the file in which the code is currently executed:

/ var / www / test-app / index.php:
& lt;? php
echo __dir__; // / Var / WWW / Test-App

/ var / www / test-app / subdir / sub-test.php:
& lt;? php
echo __dir__; // / Var / WWW / TEST-APP / Subdir

__ file __ Similarly will return the path to the currently executed file (i.e. Basename (__ File__) === __dir __ )

Answer 2, Authority 44%

__ dir __ Returns the script directory.

For example, you have a script /usr/www/site/html/index.php . You write in it

echo __dir__;

__ dir __ return the path of the folder in which this script is located, / usr / www / site / html

Answer 3

If you put your script on CRON and your paths will be without a constant dir and analogs, then the script does not find the necessary files. Although with manual launch everything will be OK.